Security readout for executives and security teams
Plain-English summary
A flaw in Linux’s AX.25 networking support can leak memory and mishandle reference counts when software connects an AX.25 socket without binding it first. Repeated triggering could affect system stability. Exploitation requires local access, and the supplied sources do not establish real-world attacks.
Executive priority
Prioritize expedited remediation on multi-user systems that expose AX.25 functionality. For systems where AX.25 is unavailable, document that finding and follow normal kernel maintenance. Account for possible application compatibility changes because the fix intentionally removes unreliable autobind behavior.
Technical view
The broken AF_AX25 autobind path fails to acquire references consistently with normal bind operations. This causes memory leakage in ax25_connect() and reference-count leakage during ax25_release(). The kernel fix removes autobind; connect() on an unbound AX.25 socket now returns EINVAL. Syzkaller found the defect.
Likely exposure
Exposure is most plausible on affected Linux kernels where AX.25 support is enabled or loadable and a local user can access AF_AX25 sockets. Systems without AX.25 functionality have substantially reduced practical exposure. The supplied version data is ambiguous, so confirm status through the kernel vendor.
Exploitation context
The CVSS 3.1 score is 7.8 with local, low-privilege access and low attack complexity. The issue was discovered through Syzkaller testing. It is not listed as KEV, and the supplied sources provide no evidence of active exploitation or a public weaponized exploit.
Researcher notes
The source demonstrates reproducible memory and reference-count leaks, but does not document privilege escalation, code execution, or confirmed confidentiality or integrity impact. Version boundaries in the supplied affected data are unclear. Validate distro-specific backports rather than relying only on upstream version numbers.
Mitigation direction
- Check the Linux distributor’s advisory for a kernel containing the cited fix or an equivalent backport.
- Install the vendor-supported fixed kernel and reboot into it.
- Test AX.25 applications because removed autobind behavior may break unbound connection attempts.
Validation and detection
- Inventory running kernel versions and determine whether AF_AX25 is enabled or loadable.
- Confirm the running kernel contains a cited stable fix or documented vendor backport.
- Review AX.25 software for connections made without an explicit socket bind.
- Review kernel logs for AX.25 reference-count warnings and unexplained memory growth.
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
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ATT&CK lookup starting points
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CVE-2025-22109 mapping review
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Open ATT&CK lookup- Severity
- High
- CVSS
- 7.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CNA and ADP enrichment extracted from CVE v5
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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:L/UI:N/S:U/C:H/I:H/A:H1.85.9LinuxVulnerability scoring details
Base CVSS 3.1 score
7.8HighVector: CVSS:3.1/AV:L/AC:L/PR:L/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.
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- CVE publishedCVE Program
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- CVE updatedCVE Program
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Source materials
- CVE List V5 sourceCVE List V5
- https://git.kernel.org/stable/c/61203fdd3e35519db9a98b6ff8983c620ffc4696CVE reference, Linux
- https://git.kernel.org/stable/c/2f6efbabceb6b2914ee9bafb86d9a51feae9cce8CVE reference, Linux
Products and packages named in the record
CWE details
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