VulnerabilityPublished 26 Oct 2026

CVE-2026-94453: libreswan security update

Affects libreswanSource GCVE Database

Mentioned vulnerabilities

Authoritative record:CVE-2026-94453· High 7.5

Not known to be exploited · CVSS 7.5 High : upgrade to 5.3.3-1.el10_2 soon.

Data as of 26 Oct 2026, 23:30 UTC

CVSS 3.1 base score

7.5High

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

Patch: Available – fixed in 5.3.3-1.el10_2

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

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

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: None: There is no loss of integrity within the impacted component.
Availability: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 13 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: 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 26 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.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, 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.

almalinux-10

What to do

Upgrade the AlmaLinux to 5.3.3-1.el10_2.

Patches and advisories

access.redhat.com/errata/RHSA-2026:89923 (opens in a new tab)

Affected software

Product	Affected	Fixed in
AlmaLinux 10libreswan	Affected <5.3.3-1.el10_2	Fixed in 5.3.3-1.el10_2
AlmaLinux 10libreswan-minimal	Affected <5.3.3-1.el10_2	Fixed in 5.3.3-1.el10_2

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

AI-suggested

A security update is available in libreswan version 5.3.3-1.el10_2 that addresses these vulnerabilities. Users should apply this update promptly to remediate the issues. Refer to the vendor advisory and update instructions at https://access.redhat.com/articles/11258 for detailed guidance. No additional mitigation steps are indicated by the vendor.

Description

Libreswan, an IPsec and IKE implementation for Linux, has multiple security vulnerabilities including a use-after-free bug in IKEv2 when using IKE-over-TCP (CVE-2026-94453), a denial of service via bogus X.509 certificates (CVE-2026-77205), and a null pointer dereference in PKCS#7 bundles with no certificates (CVE-2026-77207). These issues affect versions prior to 5.3.3-1.el10_2. A security update fixing these vulnerabilities is available.

Impact

Successful exploitation of the IKEv2 use-after-free vulnerability could lead to memory corruption, potentially causing crashes or other unintended behavior. The denial of service vulnerability allows an attacker to disrupt service by sending malformed X.509 certificates. The null pointer dereference could also cause application crashes. These issues impact the stability and security of VPN tunnels established using affected libreswan versions.

References

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