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CVE-2026-45984

gfs2: Fix use-after-free in iomap inline data write path

HIGH 7.8

At a glance

Source
NVD
EPSS
EPSS 0.18 % · percentile 8 ()
State
PUBLISHED
Published
Updated
Assigner
Linux
NVD status
Modified

Description

In the Linux kernel, the following vulnerability has been resolved: gfs2: Fix use-after-free in iomap inline data write path The inline data buffer head (dibh) is being released prematurely in gfs2_iomap_begin() via release_metapath() while iomap->inline_data still points to dibh->b_data. This causes a use-after-free when iomap_write_end_inline() later attempts to write to the inline data area. The bug sequence: 1. gfs2_iomap_begin() calls gfs2_meta_inode_buffer() to read inode metadata into dibh 2. Sets iomap->inline_data = dibh->b_data + sizeof(struct gfs2_dinode) 3. Calls release_metapath() which calls brelse(dibh), dropping refcount to 0 4. kswapd reclaims the page (~39ms later in the syzbot report) 5. iomap_write_end_inline() tries to memcpy() to iomap->inline_data 6. KASAN detects use-after-free write to freed memory Fix by storing dibh in iomap->private and incrementing its refcount with get_bh() in gfs2_iomap_begin(). The buffer is then properly released in gfs2_iomap_end() after the inline write completes, ensuring the page stays alive for the entire iomap operation. Note: A C reproducer is not available for this issue. The fix is based on analysis of the KASAN report and code review showing the buffer head is freed before use. [agruenba: Take buffer head reference in gfs2_iomap_begin() to avoid leaks in gfs2_iomap_get() and gfs2_iomap_alloc().]

Weaknesses (CWE)

  • CWE-826 — Premature Release of Resource During Expected Lifetime
  • CWE-416 — Use After Free

References

Scores

VersionScoreVectorScored by
CVSS 3.1HIGH 7.8CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HLinux
CVSS 3.1HIGH 7.8CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:Hredhat-SADP
CVSS 3.1HIGH 7.8CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HNVD · 416baaa9-dc9f-4396-8d5f-8c081fb06d67 (Secondary)
CVSS 3.1HIGH 7.8CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HNVD · 0b0ca135-0b70-47e7-9f44-1890c2a1c46c (Secondary)

European references

CERT-FR advisories

Affected configurations (NVD CPE)

Affected products

ProductVersions
Linux · Linuxaffected d0a22a4b03b8475b7aa3fa41243c26c291407844 < 1403989d1b502f4a2c0d0b42ccf1c25748442eff ; affected d0a22a4b03b8475b7aa3fa41243c26c291407844 < 1cae1bafdf9caa9b462b19af06b1a06902e4e142 ; affected d0a22a4b03b8475b7aa3fa41243c26c291407844 < 764c3c84b5683e608f43735c803a5f415046686c ; affected d0a22a4b03b8475b7aa3fa41243c26c291407844 < d87268326b277af3665237ac76a73dd9fa8e21b4 ; affected d0a22a4b03b8475b7aa3fa41243c26c291407844 < 87d4954b5c59735a99ea98cb208d47130f6dce7d ; affected d0a22a4b03b8475b7aa3fa41243c26c291407844 < 6d76febba07c40bcf358f63216d36ea68cf1c215
Linux · Linuxaffected 5.2 ; unaffected 0 < 5.2 ; unaffected 5.10.252 ≤ 5.10.* ; unaffected 5.15.202 ≤ 5.15.* ; unaffected 6.1.165 ≤ 6.1.* ; unaffected 6.6.128 ≤ 6.6.*

Sources

SourceLicence
CVE List (CVEProject cvelistV5)CVE Program Terms of Use
EPSS (FIRST.org)FIRST — attribution requested
ENISA EUVDENISA — reproduction authorised, source acknowledged
CERT-FR (ANSSI)Licence Ouverte / Etalab 2.0
NVD (NIST) via fkie-cad/nvd-json-data-feedsPublic domain — this product uses data from the NVD API but is not endorsed or certified by the NVD