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Review reviewHigh

CVE-2025-37879

Linux Linux, linux kernel, debian linux

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
7.1
EPSS
0.67%
48.6% percentile
CISA KEV
Not listed
Published
2025.05.09
PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV
Exploit probability0.67%
Technical severityCVSS 7.1

Vulnerability overview

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)

Affected product and versions

Product
Linux Linux, linux kernel, debian linux
Affected versions
>= 070b3656cf228eaaef7b28b59264c5c7cdbdd0fb < 468ff4a7c61fb811c596a7c44b6a5455e40fd12b, >= 070b3656cf228eaaef7b28b59264c5c7cdbdd0fb < a68768e280b7d0c967ea509e791bb9b90adc94a5, >= 070b3656cf228eaaef7b28b59264c5c7cdbdd0fb < c548f95688e2b5ae0e2ae43d53cf717156c7d034, >= 070b3656cf228eaaef7b28b59264c5c7cdbdd0fb < 374e4cd75617c8c2552f562f39dd989583f5c330, >= 070b3656cf228eaaef7b28b59264c5c7cdbdd0fb < d0259a856afca31d699b706ed5e2adf11086c73b, >= 4.1, < 6.1.136, >= 6.2 < 6.6.89, >= 6.7 < 6.12.26, >= 6.13 < 6.14.5, 11.0
Fixed versions
6.1.136, 6.6.89, 6.12.26, 6.14.5

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide
  1. 1
    Identify

    Confirm that Linux Linux, linux kernel, debian linux and an affected version are present.

  2. 2
    Prioritize

    Combine exploitation signals with asset exposure and business criticality.

  3. 3
    Remediate

    Follow the vendor advisory or supported update path and preserve rollback options.

  4. 4
    Verify

    Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
CWE
CWE-125