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CVE-2025-9820VulnerabilityPublished Updated

CVE-2025-9820: Red Hat Enterprise Linux 10 · Stack-based Buffer Overflow

Affects Red Hat Enterprise Linux 10Source CVE Database V5

0

Not known to be exploited · CVSS 4.0 Medium : upgrade to 10.2 when convenient.

Data as of 25 Oct 2026, 19:02 UTC

CVSS 3.1 base score
4.0Medium
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.2% chance of exploitation in 30 days – higher than 12% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 10.2
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 26 Jan 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq 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 2026-10-25.

What to do

Upgrade redhat/gnutls to 10.2.

Affected software

ProductAffectedFixed in
Red HatRed Hat Enterprise Linux 10Affected–Fixed in–
Red HatRed Hat Enterprise Linux 8Affected–Fixed in–
Red HatRed Hat Enterprise Linux 9Affected–Fixed in–
Red HatRHEL-8 based Middleware ContainersAffected–Fixed in–
Red HatRHEL-8 based Middleware ContainersAffected–Fixed in–
Red HatRHEL-8 based Middleware ContainersAffected–Fixed in–
Red HatRHEL-8 based Middleware ContainersAffected–Fixed in–
Red HatRHEL-8 based Middleware ContainersAffected–Fixed in–
Red HatRHEL-8 based Middleware ContainersAffected–Fixed in–
Red HatRHEL-8 based Middleware ContainersAffected–Fixed in–
Red HatCert Manager support for Red Hat OpenShift release 1.18Affected–Fixed in–
Red HatCert Manager support for Red Hat OpenShift release 1.18Affected–Fixed in–
Red HatCert Manager support for Red Hat OpenShift release 1.18Affected–Fixed in–
Red HatCert Manager support for Red Hat OpenShift release 1.18Affected–Fixed in–
Red HatCert Manager support for Red Hat OpenShift release 1.18Affected–Fixed in–
Red HatRed Hat Ceph Storage 8Affected–Fixed in–
Red HatRed Hat Discovery 2Affected–Fixed in–
Red HatRed Hat Discovery 2Affected–Fixed in–
Red HatRed Hat Hardened ImagesAffected–Fixed in–
Red HatRed Hat Insights proxy 1.5Affected–Fixed in–
Red HatRed Hat Update Infrastructure 5Affected–Fixed in–
Red HatRed Hat Update Infrastructure 5Affected–Fixed in–
Red HatRed Hat Update Infrastructure 5Affected–Fixed in–
Red HatRed Hat Update Infrastructure 5Affected–Fixed in–
Red HatRed Hat Enterprise Linux 6Affected–Fixed in–
Red HatRed Hat Enterprise Linux 7Affected–Fixed in–
Red HatRed Hat OpenShift Container Platform 4Affected–Fixed in–
Red Hatredhat/gnutlspkg:rpm/redhat/gnutlsOther threatsAffected
  • =10
  • <10.2
Fixed in
  • 10.2

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

AI-suggested

Red Hat has released official security updates for GnuTLS in Red Hat Enterprise Linux 10 that fix this vulnerability. Users should upgrade to the patched GnuTLS packages (e.g., gnutls-3.8.10-3.el10_1 or later) as provided in advisories RHSA-2026:3477 and RHSA-2026:13812. Applying these updates fully mitigates the vulnerability. No additional mitigation steps are required beyond applying the vendor-provided patches.

Description

A flaw was found in the GnuTLS library, specifically in the gnutls_pkcs11_token_init() function that handles PKCS#11 token initialization. When a token label longer than expected is processed, the function writes past the end of a fixed-size stack buffer. This programming error can cause the application using GnuTLS to crash or, in certain conditions, be exploited for code execution. As a result, systems or applications relying on GnuTLS may be vulnerable to a denial of service or local privilege escalation attacks.

References

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