CVE-2026-24881Network attack vector

Unauthenticated code execution via oversized session key

Published Jan 27, 2026 · Updated Jan 27, 2026

Stack-based buffer overflow in GnuPG 2.5.13 through 2.5.16 allows remote attackers to execute code via crafted CMS messages. During PKDECRYPT --kem=CMS handling, gpg-agent fails to reject an oversized wrapped session key before processing overflows stack storage. Processing an attacker-supplied S/MIME EnvelopedData message can crash gpg-agent and corrupt memory; code execution requires successful exploitation of that corruption.

CVSS severity8.1
High
EPSS probability1.72%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stack-based buffer overflow in GnuPG 2.5.13 through 2.5.16 allows remote attackers to execute code via crafted CMS messages. During PKDECRYPT --kem=CMS handling, gpg-agent fails to reject an oversized wrapped session key before processing overflows stack storage. Processing an attacker-supplied S/MIME EnvelopedData message can crash gpg-agent and corrupt memory; code execution requires successful exploitation of that corruption.

The record

CVE
CVE-2026-24881
Published
Jan 27, 2026
Updated
Jan 27, 2026
Vendor
The GnuPG Project
Product
GnuPG
Classifications
CWE-121, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 27, 2026CVE publishedPublication date reported by the CVE source.
  2. Jan 27, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=2.5.13 <2.5.17

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The GnuPG Project · GnuPGversion=2.5.13 <2.5.17

Published CVSS scores

9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
8.1MITRECVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-121Stack-based Buffer Overflow
T1203Exploitation for Client Execution

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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