Security readout for executives and security teams
CVE-2025-9820 is a GnuTLS memory-safety flaw in PKCS#11 token initialization. A too-long token label can overflow a stack buffer. Most likely impact is application crashes in systems using GnuTLS with PKCS#11 token workflows; sources also note possible code execution or local privilege escalation under certain conditions. Exposure is most plausible on Linux systems, appliances, or containers using affected GnuTLS builds and PKCS#11 token initialization, including smartcard, HSM, or certificate-token workflows. Internet exposure is not established by the sources. Treat this as a moderate operational security issue. It is not currently supported as actively exploited, but patching should be scheduled promptly for affected Linux platforms and prioritized where PKCS#11-backed authentication or certificate infrastructure is business-critical. Mitigation focus: Apply relevant vendor updates from Red Hat or upstream GnuTLS guidance.; Prioritize systems using PKCS#11, smartcards, HSMs, or token initialization.; Update affected RHEL-based container images and redeploy dependent workloads..
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
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ATT&CK lookup starting points
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CWE-121: Exact CWE lookup
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Open ATT&CK lookupExecution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCredential and access behavior lookup
The CVE wording references authentication or credential exposure, so valid-account and credential-access review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupPrivilege behavior lookup
The CVE wording references privilege impact, so privilege escalation and authorization behavior review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupContainer behavior lookup
The affected technology mentions containers, so container-specific ATT&CK technique review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2025-9820 mapping review
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Open ATT&CK lookup- Severity
- Medium
- CVSS
- 4 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
SSVC decision data
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L2.51.4redhatVulnerability scoring details
Base CVSS 3.1 score
4MediumVector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- Source timelineredhat
Reported to Red Hat.
- Source timelineredhat
Made public.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 sourceCVE List V5
- RHSA-2026:13812CVE reference, redhat · vendor-advisory, x_refsource_REDHAT
- RHSA-2026:3477CVE reference, redhat · vendor-advisory, x_refsource_REDHAT
- RHSA-2026:4188CVE reference, redhat · vendor-advisory, x_refsource_REDHAT
- RHSA-2026:4655CVE reference, redhat · vendor-advisory, x_refsource_REDHAT
- RHSA-2026:4943CVE reference, redhat · vendor-advisory, x_refsource_REDHAT
- RHSA-2026:5585CVE reference, redhat · vendor-advisory, x_refsource_REDHAT
- RHSA-2026:5606CVE reference, redhat · vendor-advisory, x_refsource_REDHAT
- RHSA-2026:7329CVE reference, redhat · vendor-advisory, x_refsource_REDHAT
- RHSA-2026:7477CVE reference, redhat · vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/security/cve/CVE-2025-9820CVE reference, redhat · vdb-entry, x_refsource_REDHAT
- RHBZ#2392528CVE reference, redhat · issue-tracking, x_refsource_REDHAT
- https://gitlab.com/gnutls/gnutls/-/commit/1d56f96f6ab5034d677136b9d50b5a75dff0faf5CVE reference, redhat
- https://gitlab.com/gnutls/gnutls/-/issues/1732CVE reference, redhat
- https://www.gnutls.org/security-new.html#GNUTLS-SA-2025-11-18CVE reference, redhat
- https://cert-portal.siemens.com/productcert/html/ssa-032379.htmlCVE reference, siemens-SADP
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Stack-based Buffer Overflow
Stack-based Buffer Overflow represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.