CVE-2026-64057 (GCVE-0-2026-64057)

Vulnerability from cvelistv5 – Published: 2026-07-19 15:39 – Updated: 2026-07-20 13:42
VLAI
Title
afs: Fix the locking used by afs_get_link()
Summary
In the Linux kernel, the following vulnerability has been resolved: afs: Fix the locking used by afs_get_link() The afs filesystem in the kernel doesn't do locking correctly for symbolic links. There are a number of problems: (1) It doesn't do any locking around afs_read_single() to prevent races between multiple ->get_link() calls, thereby allowing the possibility of leaks. (2) It doesn't use RCU barriering when accessing the buffer pointers during RCU pathwalk. (3) It can race with another thread updating the contents of the symlink if a third party updated it on the server. Fix this by the following means: (0) Move symlink handling into its own file as this makes it more complicated. (1) Take the validate_lock around afs_read_single() to prevent races between multiple ->get_link() calls. (2) Keep a separate copy of the symlink contents with an rcu_head. This is always going to be a lot smaller than a page, so it can be kmalloc'd and save quite a bit of memory. It also needs a refcount for non-RCU pathwalk. (3) Split the symlink read and write-to-cache routines in afs from those for directories. (4) Discard the I/O buffer as soon as the write-to-cache completes as this is a full page (plus a folio_queue). (5) If there's no cache, discard the I/O buffer immediately after reading and copying if there is no cache.
Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: eae9e78951bb02a7b94a9adef6e981413d13c564 , < 77ea917cbed62882a33114b1e23ededb977e4287 (git)
Affected: eae9e78951bb02a7b94a9adef6e981413d13c564 , < c0410adf3da6db46f3513411fcf95e63c2f1d1ad (git)
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Linux Linux Affected: 6.14
Unaffected: 0 , < 6.14 (semver)
Unaffected: 7.0.11 , ≤ 7.0.* (semver)
Unaffected: 7.1 , ≤ * (original_commit_for_fix)
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{
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            "fs/afs/symlink.c",
            "fs/afs/validation.c",
            "fs/afs/yfsclient.c"
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    "datePublished": "2026-07-19T15:39:38.321Z",
    "dateReserved": "2026-07-19T07:54:57.030Z",
    "dateUpdated": "2026-07-20T13:42:54.729Z",
    "state": "PUBLISHED"
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    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-07-20T17:08:46+00:00",
      "cve": "CVE-2026-64057",
      "id": "CVE-2026-64057",
      "initial_release_date": "2026-07-19T00:00:00+00:00",
      "product_status:known_affected": "76",
      "product_status:known_not_affected": "198",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: afs: Fix the locking used by afs_get_link()",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-64057.json",
      "version": "3"
    }
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.