VulnerabilityPublished 17 Mar 2026Updated 19 Mar 2026

CVE-2026-3632: Red Hat Enterprise Linux 10 · Improper Validation of Syntactic Correctness of Input

Affects Red Hat Enterprise Linux 10Source CVE Database V5

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Not known to be exploited · CVSS 3.9 Low.

Data as of 30 Oct 2026, 11:52 UTC

CVSS 3.1 base score

3.9Low

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

EPSS: 0.2% chance of exploitation in 30 days – higher than 11% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

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

Attack Vector: Network
Attack Complexity: High
Privileges Required: High
User Interaction: Required
Scope: Unchanged
Confidentiality: Low
Integrity: Low
Availability: Low

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: High: A successful attack depends on conditions beyond the attacker's control. That is, a successful attack cannot be accomplished at will, but requires the attacker to invest in some measurable amount of effort in preparation or execution against the vulnerable component before a successful attack can be expected. For example, a successful attack may require an attacker to: gather knowledge about the environment in which the vulnerable target/component exists; prepare the target environment to improve exploit reliability; or inject themselves into the logical network path between the target and the resource requested by the victim in order to read and/or modify network communications (e.g., a man in the middle attack).
Privileges Required: High: The attacker is authorized with (i.e., requires) privileges that provide significant (e.g., administrative) control over the vulnerable component that could affect component-wide settings and files.
User Interaction: Required: Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited.
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: Low: Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the impacted component are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 17 Mar 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 30 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.

What to do

Affected software

Product	Affected	Fixed in
Red Hat Enterprise Linux 10libsoup3	Affected–	Fixed in–
Red Hat Enterprise Linux 6libsoup	Affected–	Fixed in–
Red Hat Enterprise Linux 7libsoup	Affected–	Fixed in–
Red Hat Enterprise Linux 8libsoup	Affected–	Fixed in–
Red Hat Enterprise Linux 9libsoup	Affected–	Fixed in–

AI-suggested

Organizations should monitor Red Hat security advisories for patches addressing CVE-2026-3632 and apply them promptly once available. Since the vulnerability involves improper hostname validation in libsoup, updating to a fixed version of libsoup or Red Hat Enterprise Linux 10 that includes the patch is the most effective mitigation. In the interim, administrators should audit applications using libsoup to understand exposure and consider restricting or monitoring network traffic involving HTTP headers for anomalies indicative of request smuggling. Employing network-level protections such as Web Application Firewalls (WAFs) that can detect and block HTTP request smuggling attempts may provide additional defense. Limiting privileges and reducing user interaction with vulnerable components can also reduce exploitation risk. Finally, organizations should implement robust internal network segmentation to minimize the impact of SSRF attacks that might arise from this vulnerability.

Description

A flaw was found in libsoup, a library used by applications to send network requests. This vulnerability occurs because libsoup does not properly validate hostnames, allowing special characters to be injected into HTTP headers. A remote attacker could exploit this to perform HTTP smuggling, where they can send hidden, malicious requests alongside legitimate ones. In certain situations, this could lead to Server-Side Request Forgery (SSRF), enabling an attacker to force the server to make unauthorized requests to other internal or external systems. The impact is low, as SoupServer is not actually used in internet infrastructure.

Impact

The primary impact of CVE-2026-3632 is the potential for HTTP request smuggling and SSRF attacks, which can undermine the confidentiality and integrity of internal systems by allowing unauthorized requests to be made from the vulnerable server. However, the overall impact is low because the vulnerable component, SoupServer, is not widely deployed in internet-facing roles, reducing exposure to external attackers. The requirement for high privileges and user interaction further limits the likelihood of exploitation. For organizations, this vulnerability could be leveraged in targeted attacks where an attacker has some level of access or can trick a privileged user into initiating malicious requests. If exploited, it could facilitate lateral movement within internal networks or access to restricted resources. Nonetheless, the limited use of the affected library in critical infrastructure means the global impact is expected to be minimal. Organizations relying heavily on Red Hat Enterprise Linux 10 in internal environments should still consider the risk, especially if they use applications dependent on libsoup for network communications.

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 25 Mar 2026, 00:53 UTC

Technical details

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