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CVE-2025-37879

Status: ModifiedHigh (7.1)—

In the Linux kernel, the following vulnerability has been resolved:

9p/net: fix improper handling of bogus negative read/write replies

In p9_client_write() and p9_client_read_once(), if the server incorrectly replies with success but a negative write/read count then we would consider written (negative) <= rsize (positive) because both variables were signed.

Make variables unsigned to avoid this problem.

The reproducer linked below now fails with the following error instead of a null pointer deref: 9pnet: bogus RWRITE count (4294967295 > 3)

CVSS

Exploitation probability (EPSS)

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

🎯 ATT&CK techniques

How this vulnerability is exploited and what the attacker gains, in MITRE ATT&CK terms.

Vulnerabilidad local (AV:L) en kernel Linux sin interacción del usuario que permite DoS por null pointer deref; requiere privilegios (PR:L). El CWE-125 (out-of-bounds read) y manejo de valores negativos sugiere posible ejecución de código tras corregir el deref.

Inferred by our analysis agent from the official description, CVSS vector and CWE, and checked by a supervisor. May contain errors.

🛡️ ATT&CK mitigations that cover these techniques

Execution PreventionThreat Intelligence ProgramRestrict Web-Based ContentPrivileged Account ManagementLimit Software InstallationBehavior Prevention on Endpoint

Affected technologies (2)

Debian — Debian LinuxLinux — Linux Kernel

CWEs

References

Raw JSON (NVD)

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      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\n9p/net: fix improper handling of bogus negative read/write replies\n\nIn p9_client_write() and p9_client_read_once(), if the server\nincorrectly replies with success but a negative write/read count then we\nwould consider written (negative) <= rsize (positive) because both\nvariables were signed.\n\nMake variables unsigned to avoid this problem.\n\nThe reproducer linked below now fails with the following error instead\nof a null pointer deref:\n9pnet: bogus RWRITE count (4294967295 > 3)"
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