CVE-2026-8388VulnerabilityPublished 27 May 2026Updated 21 Oct 2026

SUSE · security update for thunderbird

Affects SUSESource GCVE Database

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Mentioned vulnerabilities

Authoritative record:CVE-2026-8388· Medium 6.5

Not known to be exploited · CVSS 6.5 Medium · patch available : update SUSE when convenient.

Data as of 30 Oct 2026, 06:59 UTC

CVSS 3.1 base score

6.5Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.2% chance of exploitation in 30 days – higher than 15% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: Low
Integrity: Low
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the impacted component.
Integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact on the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 12 May 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

bundesamt-f-r-sicherheit-in-de

What to do

Affected software

Product	Affected	Fixed in
SUSE Product Security Team SUSE	Affected <150.0.3	Fixed in 150.0.3

AI-suggested

Red Hat has released an updated Thunderbird package (version 140.11.0-1.el9_6) for Red Hat Enterprise Linux 9.6 Extended Update Support that addresses these vulnerabilities. Users should apply the official update as described in the Red Hat advisory (https://access.redhat.com/articles/11258) to remediate the issues. No additional mitigation steps are indicated beyond applying the vendor-provided update.

Description

This update for MozillaFirefox fixes the following issues - Update to Firefox Extended Support Release 140.11.0 ESR MFSA 2026-48 (bsc#1265212). MFSA 2026-48: - CVE-2026-8388: Incorrect boundary conditions in the JavaScript Engine: JIT component. - CVE-2026-8391: Other issue in the JavaScript Engine component. - CVE-2026-8401: Sandbox escape in the Profile Backup component. - CVE-2026-8946: Incorrect boundary conditions in the Audio/Video: Web Codecs component. - CVE-2026-8947: Use-after-free in the DOM: Bindings (WebIDL) component. - CVE-2026-8949: Integer overflow in the Widget: Win32 component. - CVE-2026-8950: Same-origin policy bypass in the Networking: HTTP component. - CVE-2026-8953: Sandbox escape due to use-after-free in the Disability Access APIs component. - CVE-2026-8954: Incorrect boundary conditions, integer overflow in the Audio/Video component. - CVE-2026-8955: Privilege escalation in the DOM: Workers component. - CVE-2026-8956: Integer overflow in the Networking: JAR component. - CVE-2026-8957: Privilege escalation in the Enterprise Policies component. - CVE-2026-8958: Information disclosure, sandbox escape in the Security: Process Sandboxing component. - CVE-2026-8959: Sandbox escape due to incorrect boundary conditions in the Widget: Win32 component. - CVE-2026-8961: Spoofing issue in the Form Autofill component. - CVE-2026-8962: Mitigation bypass in the DOM: Security component. - CVE-2026-8968: Denial-of-service due to invalid pointer in the Audio/Video: Web Codecs component. - CVE-2026-8970: Privilege escalation in the Security component. - CVE-2026-8974: Memory safety bugs fixed in Firefox ESR 140.11 and Firefox 151. - CVE-2026-8975: Memory safety bugs fixed in Firefox ESR 115.36, Firefox ESR 140.11 and Firefox 151.

Impact

The vulnerabilities collectively could allow attackers to escape sandbox restrictions, escalate privileges, cause denial-of-service conditions, disclose sensitive information, bypass security policies such as same-origin policy, and spoof user interface elements. These impacts could compromise the confidentiality, integrity, and availability of the affected system and user data when using Thunderbird. The severity of these issues is rated as Important by Red Hat, indicating a high risk if unpatched.

CWE-787Out-of-bounds Write (opens in a new tab)
Base weaknessLikelihood of exploit: HighCWE Top 25 (2025): #5
The product writes data past the end, or before the beginning, of the intended buffer.
Requirements · Language Selection
Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
Architecture and Design · Libraries or Frameworks
Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
Operation · Build and Compilation · Environment Hardening
Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index…
OWASP Cheat Sheets
XML Security (opens in a new tab)
Mass Assignment (opens in a new tab)
OWASP ASVS 4.0.3
V13.3.1 (opens in a new tab)
V5.1.4 (opens in a new tab)
V5.1.3 (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
CWE-475Undefined Behavior for Input to API (opens in a new tab)
Base weakness
The behavior of this function is undefined unless its control parameter is set to a specific value.
CWE-653Improper Isolation or Compartmentalization (opens in a new tab)
Class weaknessOWASP Top 10 A06:2025: Insecure Design (opens in a new tab)
The product does not properly compartmentalize or isolate functionality, processes, or resources that require different privilege levels, rights, or permissions.
Architecture and Design
Break up privileges between different modules, objects, or entities. Minimize the interfaces between modules and require strong access control between them.
OWASP Cheat Sheets
Secure Design Principles (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
CWE-825Expired Pointer Dereference (opens in a new tab)
Base weakness
The product dereferences a pointer that contains a location for memory that was previously valid, but is no longer valid.
Architecture and Design
Choose a language that provides automatic memory management.
Implementation
When freeing pointers, be sure to set them to NULL once they are freed. However, the utilization of multiple or complex data structures may lower the usefulness of this strategy.
OWASP Cheat Sheets
XML Security (opens in a new tab)
Mass Assignment (opens in a new tab)
OWASP ASVS 4.0.3
V13.3.1 (opens in a new tab)
V5.1.4 (opens in a new tab)
V5.1.3 (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
CWE-190Integer Overflow or Wraparound (opens in a new tab)
Base weaknessLikelihood of exploit: Medium
The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.
Requirements
Ensure that all protocols are strictly defined, such that all out-of-bounds behavior can be identified simply, and require strict conformance to the protocol.
Requirements · Language Selection
Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
Architecture and Design · Libraries or Frameworks
Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
OWASP Cheat Sheets
XML Security (opens in a new tab)
Mass Assignment (opens in a new tab)
OWASP ASVS 4.0.3
V5.4.3 (opens in a new tab)
V13.3.1 (opens in a new tab)
V5.1.4 (opens in a new tab)
Attack patterns
Forced Integer Overflow (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
CWE-266Incorrect Privilege Assignment (opens in a new tab)
Base weaknessOWASP Top 10 A06:2025: Insecure Design (opens in a new tab)
A product incorrectly assigns a privilege to a particular actor, creating an unintended sphere of control for that actor.
Architecture and Design · Operation
Very carefully manage the setting, management, and handling of privileges. Explicitly manage trust zones in the software.
Architecture and Design · Operation · Environment Hardening
Run your code using the lowest privileges that are required to accomplish the necessary tasks. If possible, create isolated accounts with limited privileges that are only used for a single task. That way, a successful attack will not immediately give the attacker access to the rest of the software or its environment.
OWASP Cheat Sheets
Docker Security (opens in a new tab)
Third Party Javascript Management (opens in a new tab)
Virtual Patching (opens in a new tab)
Secure Design Principles (opens in a new tab)
OWASP ASVS 4.0.3
V1.4.4 (opens in a new tab)
V1.4.5 (opens in a new tab)
V1.10.1 (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
CWE-403Exposure of File Descriptor to Unintended Control Sphere (File Descriptor Leak) (opens in a new tab)
Base weakness
A process does not close sensitive file descriptors before invoking a child process, which allows the child to perform unauthorized I/O operations using those descriptors.
CWE-472External Control of Assumed-Immutable Web Parameter (opens in a new tab)
Base weaknessOWASP Top 10 A06:2025: Insecure Design (opens in a new tab)
The web application does not sufficiently verify inputs that are assumed to be immutable but are actually externally controllable, such as hidden form fields.
Implementation · Input Validation
Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
Implementation · Input Validation
Inputs should be decoded and canonicalized to the application's current internal representation before being validated (CWE-180). Make sure that the application does not decode the same input twice (CWE-174).
OWASP Cheat Sheets
Secure Design Principles (opens in a new tab)
Attack patterns
XML Schema Poisoning (opens in a new tab)
Session Credential Falsification through Manipulation (opens in a new tab)
Accessing/Intercepting/Modifying HTTP Cookies (opens in a new tab)
Manipulating Opaque Client-based Data Tokens (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
CWE-358Improperly Implemented Security Check for Standard (opens in a new tab)
Base weakness
The product does not implement or incorrectly implements one or more security-relevant checks as specified by the design of a standardized algorithm, protocol, or technique.

GCVE source: db.gcve.eu
Csaf Category: csaf_security_advisory
Csaf Version: 2.0
Publisher: Red Hat Product Security
Advisory ID: RHSA-2026:21381
CVE Count: 19
Additional Cves: CVE-2026-8391, CVE-2026-8401, CVE-2026-8946, CVE-2026-8947, CVE-2026-8950, CVE-2026-8953, CVE-2026-8954, CVE-2026-8955, CVE-2026-8956, CVE-2026-8957, CVE-2026-8958, CVE-2026-8959, CVE-2026-8961, CVE-2026-8962, CVE-2026-8968, CVE-2026-8970, CVE-2026-8974, CVE-2026-8975

References

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 15 Jul 2026, 15:28 UTC

Public exploits and detectionGitHub proofs of concept

WeaknessesCWE-787, CWE-475, CWE-653 +6

Technical details

References

Community reviews

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