CVE-2026-93011VulnerabilityPublished 29 Oct 2026

Out-of-bounds Write

Source GCVE Database

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Mentioned vulnerabilities

CVE-2026-2291

Authoritative record:CVE-2026-93011· Medium 5.3

Not known to be exploited · CVSS 5.3 Medium : upgrade Red Hat Ceph Storage 9 dnsmasq to 2.93 when convenient.

Data as of 29 Oct 2026, 16:54 UTC

CVSS 3.1 base score

5.3Medium

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

Thin evidence

One scorer or none

CVSS scores by source
CNA (redhat)	CVSS 3.1	5.3

Patch: Available – fixed in 2.93

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: None
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: None: There is no loss of confidentiality within 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 29 Oct 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.

ghsa-2jq5-wc7q-j2fc

What to do

Upgrade dnsmasq to 2.93.

Affected software

Product	Affected	Fixed in
npmdnsmasq`pkg:npm/dnsmasq`Other threats	Affected <2.93	Fixed in 2.93

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Meanwhile, to reduce risk: (1) do not enable DNSSEC validation (--dnssec or --trust-anchor) unless necessary; (2) build dnsmasq without the HAVE_DNSSEC compile-time option (default); (3) if DNSSEC validation is required, restrict dnsmasq to trusted upstream resolvers. These mitigations effectively reduce exposure to the vulnerability.

Description

A vulnerability in dnsmasq's DNSSEC validator allows a heap out-of-bounds write of 1-3 bytes past a domain-name buffer due to reduced internal buffer sizes. This flaw requires DNSSEC support to be compiled in and enabled at runtime. The overwrite affects adjacent heap metadata but has not been shown to cause crashes or control-flow impacts. The vulnerability is rated medium severity with a CVSS score of 5.3. Mitigations include not enabling DNSSEC validation unless required and restricting dnsmasq to trusted upstream resolvers if DNSSEC is needed.

Impact

The vulnerability allows a bounded heap out-of-bounds write of 1-3 bytes to adjacent heap metadata during DNSSEC validation. This could potentially corrupt heap metadata but has not been shown to cause crashes, denial of service, or privilege escalation. There is no impact on confidentiality or availability. The flaw requires DNSSEC support to be enabled both at compile-time and runtime, limiting exposure. Overall, the impact is low to moderate integrity risk without demonstrated exploitation or control-flow impact.

Summary

Dnsmasq contains a vulnerability (CVE-2026-93011) where the DNSSEC validator can write a few bytes beyond the allocated domain-name buffer when converting names to and from DNS wire format. This occurs after a reduction in internal buffer sizes introduced in versions after 2.90. The vulnerability requires DNSSEC support to be compiled in (off by default) and enabled at runtime via flags. An attacker capable of causing the server to validate a crafted DNSSEC response may overwrite a small amount of adjacent heap metadata on a never-freed startup heap chunk. No crashes or control-flow hijacks have been demonstrated despite multiple attempts. This issue is a follow-on to CVE-2026-2291 and affects dnsmasq versions shipping 2.93 buffers, but current Red Hat packages (2.90 or earlier) do not contain the vulnerable buffers. The flaw is rated moderate due to the limited overwrite size and lack of demonstrated impact on availability or confidentiality.

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).

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 29 Oct 2026, 16:54 UTC

WeaknessesCWE-787

Technical details

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