Security readout for executives and security teams
Plain-English summary
A malicious S/MIME encrypted message can crash GnuPG’s gpg-agent when it handles an oversized wrapped session key. The public record says denial of service is easy, and memory corruption could allow remote code execution. Treat this as urgent where GnuPG processes untrusted CMS/S/MIME mail or content.
Executive priority
High priority for organizations using GnuPG in email security, automated decryption, or document-processing workflows. The main proven impact is service disruption, but the memory-corruption risk raises the urgency for patching exposed systems.
Technical view
CVE-2026-24881 is a stack-based buffer overflow in GnuPG gpg-agent during PKDECRYPT--kem=CMS handling of CMS EnvelopedData with an oversized wrapped session key. Sources describe GnuPG before 2.5.17 and identify GnuPG 2.5.13. CVSS 3.1 is 8.1 with network attack vector and high confidentiality, integrity, and availability impact.
Likely exposure
Exposure is most likely in systems using GnuPG or gpg-agent to decrypt CMS/S/MIME content from untrusted sources. The provided affected data specifically lists GnuPG 2.5.13, while the title states GnuPG before 2.5.17.
Exploitation context
The bundle does not show CISA KEV listing or confirmed active exploitation. It states denial of service is easy and memory corruption could lead to remote code execution. Attack complexity is rated high in the CVSS vector.
Researcher notes
Evidence supports CWE-121 stack overflow in gpg-agent PKDECRYPT--kem=CMS handling. The bundle does not provide public exploit details, confirmed exploitation, or complete downstream vendor impact. Validate exposure through version inventory and actual CMS/S/MIME processing paths.
Mitigation direction
- Upgrade GnuPG to 2.5.17 or a vendor-fixed build where available.
- Check Red Hat and GnuPG advisories for distribution-specific package status.
- Reduce automated processing of untrusted S/MIME CMS messages until patched.
- Monitor gpg-agent crashes or abnormal restarts on mail-processing hosts.
- Prioritize systems that decrypt external S/MIME content.
Validation and detection
- Inventory GnuPG versions on servers, desktops, and mail-processing systems.
- Confirm whether gpg-agent handles CMS/S/MIME decryption workflows.
- Identify systems running GnuPG 2.5.13 or versions before 2.5.17.
- Review package vendor status for CVE-2026-24881.
- Check logs for unexplained gpg-agent crashes tied to S/MIME handling.
Public sources used
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
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-121: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
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 lookupCVE-2026-24881 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- High
- CVSS
- 8.1 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
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
2 official scoresWe 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:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H2.25.9mitreCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H2.25.9redhat-SADPVulnerability scoring details
Base CVSS 3.1 score
8.1HighVector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Base CVSS 3.1 score
8.1HighVector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
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.
- ADP timelineredhat-SADP
Made public.
- CVE publishedCVE Program
The CVE record was published.
- ADP timelineredhat-SADP
Reported to Red Hat.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
- 2026-01-27T19:02:29.973Z: Reported to Red Hat.
- 2026-01-27T18:36:56.727Z: Made public.
Source materials
- CVE List V5 sourceCVE List V5
- https://www.openwall.com/lists/oss-security/2026/01/27/8CVE reference, mitre
- https://dev.gnupg.org/T8044CVE reference, mitre
- https://access.redhat.com/security/cve/CVE-2026-24881CVE reference, redhat-SADP · vdb-entry, x_refsource_REDHAT
- RHBZ#2433480CVE reference, redhat-SADP · issue-tracking, x_refsource_REDHAT
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-24881.jsonCVE reference, redhat-SADP · x_sadp-csaf-vex
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.