CVE-2025-30258
Description
A flaw was found in GnuPG. In affected versions, if a user chooses to import a certificate with certain crafted subkey data that lacks a valid backsig or that has incorrect usage flags, the user loses the ability to verify signatures made from certain other signing keys, leading to a verification denial of service.
Statement
This vulnerability is rated as LOW impact. This is because it exists in GnuPG's certificate import logic. When a user imports a crafted certificate containing a subkey with a missing/invalid backsig (binding signature proving subkey-primary key association) or malformed usage flags, GnuPG fails to isolate the invalid key material, corrupting internal key selection state. This prevents verification of legitimate signing keys which is a denial of service extending beyond the malicious certificate. Exploitation requires user action to import an untrusted certificate.
Mitigation
There is no available mitigation for this vulnerability.
However as a general security procedure,users should exercise caution and avoid importing GnuPG certificates from untrusted or unverified sources. Only import certificates that are known to be legitimate and from trusted entities.
Update to GnuPG version 2.5.5 or later to resolve this issue.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 2.7 | 4.7 | N/A |
| Attack Vector | Local | Local | N/A |
| Attack Complexity | High | High | N/A |
| Privileges Required | None | Low | N/A |
| User Interaction | Required | None | N/A |
| Scope | Changed | Unchanged | N/A |
| Confidentiality | None | None | N/A |
| Integrity Impact | None | None | N/A |
| Availability Impact | Low | High | N/A |
Vector
Red Hat: CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:C/C:N/I:N/A:L
NVD: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Integrity,Availability
Technical Impact: DoS: Crash, Exit, or Restart; Unexpected State
The data which were produced as a result of a function call could be in a bad state upon return. If the return value is not checked, then this bad data may be used in operations, possibly leading to a crash or other unintended behaviors.
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