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TI-2026-45374 Aliases CVE-2026-63808GHSA-rp7p-3v5m-f8gg

exfat: fix potential use-after-free in exfat_find_dir_entry()

Priority MEDIUM 49CWE-416Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Code execution
Confidentiality · integrity · availability
High · High · High
Fix status
Partial Red Hat: 10 fixed, 1 without a fix

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat. Impact type from CWE-416 and the CVSS impact.

Summary

In the Linux kernel, the following vulnerability has been resolved: exfat: fix potential use-after-free in exfat_find_dir_entry() In exfat_find_dir_entry(), the buffer_head obtained from exfat_get_dentry() is released with brelse(bh) before the fall-through TYPE_EXTEND branch reads the directory entry through ep (which points into bh->b_data): brelse(bh); if (entry_type == TYPE_EXTEND) { ... len = exfat_extract_uni_name(ep, entry_uniname); ... } After brelse() drops our reference, nothing guarantees that the underlying page backing bh->b_data remains valid for the subsequent exfat_extract_uni_name() read. This is the same pattern fixed in commit fc961522ddbd ("exfat: Fix potential use after free in exfat_load_upcase_table()"). Move brelse(bh) so it runs after ep is no longer dereferenced on each branch. Confirmed on QEMU x86_64 with CONFIG_KASAN=y + CONFIG_DEBUG_PAGEALLOC=y + CONFIG_PAGE_POISONING=y on linux-next, using a crafted exFAT image (long filename with same-hash collisions forcing the TYPE_EXTEND path). With a debug-only invalidate_bdev() inserted between brelse(bh) and the ep read to make the stale-deref window deterministic, the unpatched kernel faults: BUG: KASAN: use-after-free in exfat_find_dir_entry+0x133b/0x15a0 BUG: unable to handle page fault for address: ffff88801a5fa0c2 Oops: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN NOPTI RIP: 0010:exfat_find_dir_entry+0x1188/0x15a0 With this patch applied, the same instrumented harness completes cleanly under the same sanitizer stack. I have not reproduced a crash on an uninstrumented kernel under ordinary reclaim; the instrumented A/B establishes the lifetime violation and that the patch closes it, not an unaided triggerability claim.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00527 44th percentileScored 2026-11-07
Fix Partial Linux (Linux): 5.10.260, 5.15.211, 6.1.177 +5Red Hat: 2 advisoriesRed Hat: 10 fixed, 1 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
LinuxLinux5.7 and later5.10.260, 5.15.211, 6.1.177, 6.6.144, 6.12.95, 6.18.38, 7.1.3, 7.2Patch availableCNA
  • Linux VendorLinux Affected 5.7 and later Fixed in 5.10.260, 5.15.211, 6.1.177, 6.6.144, 6.12.95, 6.18.38, 7.1.3, 7.2 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*5.7 to before 5.10.260; 5.11 to before 5.15.211; 5.16 to before 6.1.177; 6.2 to before 6.6.144; 6.7 to before 6.12.95; 6.13 to before 6.18.38; 6.19 to before 7.1.3VulnerableLinux
  • cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions 5.7 to before 5.10.260; 5.11 to before 5.15.211; 5.16 to before 6.1.177; 6.2 to before 6.6.144; 6.7 to before 6.12.95; 6.13 to before 6.18.38; 6.19 to before 7.1.3 Vulnerable ·Linux

Remediation

  • Fix · CNA Linux (Linux) Fixed in 5.10.260, 5.15.211, 6.1.177, 6.6.144, 6.12.95, 6.18.38, 7.1.3, 7.2

Red Hat 2 advisories

  • RHSA-2026:63129 Released 2026-09-04 · Red Hat rating Important
    kernel security, bug fix, and enhancement update
    • Red Hat Enterprise Linux AppStream (v. 9) kernel-64k-debug-devel-5.14.0-687.44.1.el9_8, kernel-64k-debug-devel-matched-5.14.0-687.44.1.el9_8, kernel-64k-devel-5.14.0-687.44.1.el9_8 +12
    • Red Hat Enterprise Linux BaseOS (v. 9) kernel-5.14.0-687.44.1.el9_8, kernel-64k-5.14.0-687.44.1.el9_8, kernel-64k-core-5.14.0-687.44.1.el9_8 +28
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) kernel-tools-libs-devel-5.14.0-687.44.1.el9_8, libperf-5.14.0-687.44.1.el9_8
    • Red Hat Enterprise Linux Real Time (v. 9) kernel-rt-5.14.0-687.44.1.el9_8, kernel-rt-64k-5.14.0-687.44.1.el9_8, kernel-rt-64k-core-5.14.0-687.44.1.el9_8 +21
    • Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt-5.14.0-687.44.1.el9_8, kernel-rt-core-5.14.0-687.44.1.el9_8, kernel-rt-debug-5.14.0-687.44.1.el9_8 +9
  • RHSA-2026:63128 Released 2026-09-04 · Red Hat rating Important
    kernel security update
    • Red Hat Enterprise Linux AppStream (v. 10) kernel-64k-debug-devel-6.12.0-211.51.1.el10_2, kernel-64k-debug-devel-matched-6.12.0-211.51.1.el10_2, kernel-64k-devel-6.12.0-211.51.1.el10_2 +12
    • Red Hat Enterprise Linux BaseOS (v. 10) kernel-6.12.0-211.51.1.el10_2, kernel-64k-6.12.0-211.51.1.el10_2, kernel-64k-core-6.12.0-211.51.1.el10_2 +29
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) kernel-tools-libs-devel-6.12.0-211.51.1.el10_2, libperf-6.12.0-211.51.1.el10_2
    • Red Hat Enterprise Linux Real Time (v. 10) kernel-rt-6.12.0-211.51.1.el10_2, kernel-rt-64k-6.12.0-211.51.1.el10_2, kernel-rt-64k-core-6.12.0-211.51.1.el10_2 +21
    • Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt-6.12.0-211.51.1.el10_2, kernel-rt-core-6.12.0-211.51.1.el10_2, kernel-rt-debug-6.12.0-211.51.1.el10_2 +9

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Enterprise Linux 9AffectedNo fix yet
Red Hat Enterprise Linux AppStream (v. 10)Fixed RHSA-2026:63128
Red Hat Enterprise Linux AppStream (v. 9)Fixed RHSA-2026:63129
Red Hat Enterprise Linux BaseOS (v. 10)Fixed RHSA-2026:63128
Red Hat Enterprise Linux BaseOS (v. 9)Fixed RHSA-2026:63129
Red Hat Enterprise Linux CodeReady Linux Builder (v. 10)Fixed RHSA-2026:63128
Red Hat Enterprise Linux CodeReady Linux Builder (v. 9)Fixed RHSA-2026:63129
Red Hat Enterprise Linux Real Time (v. 10)Fixed RHSA-2026:63128
Red Hat Enterprise Linux Real Time (v. 9)Fixed RHSA-2026:63129
Red Hat Enterprise Linux Real Time for NFV (v. 10)Fixed RHSA-2026:63128
Red Hat Enterprise Linux Real Time for NFV (v. 9)Fixed RHSA-2026:63129
Not affected: 3 products
  • Red Hat Enterprise Linux 6
  • Red Hat Enterprise Linux 7
  • Red Hat Enterprise Linux 8

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-63808
  2. 2026-10-03 Alias added: GHSA-rp7p-3v5m-f8gg
  3. 2026-10-16 CISA SSVC decision points changed
  4. 2026-10-19 Weakness changed · CISA ADP
  5. 2026-11-06 CVSS score changed · Red Hat

References

Patch 8

  • TI-2025-26358 tls: fix handling of zero-length records on the rx_list KEVCVSS 3.1CRITICAL 9.8
  • TI-2026-38352 netfilter: bridge: make ebt_snat ARP rewrite writable KEVCVSS 3.1HIGH 8.8
  • TI-2013-05264 The (1) get_user and (2) put_user API functions in the Linux kernel before 3.5.5 on the… KEVCVSS 3.1HIGH 8.8
  • TI-2022-00125 Integer overflow in kernel KEVCVSS 3.1HIGH 8.4
  • TI-2013-01864 The perf_swevent_init function in kernel/events/core.c in the Linux kernel before 3.8.9… KEVCVSS 3.1HIGH 8.4
  • TI-2021-05514 Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACE KEVCVSS 3.1HIGH 8.3
See all 15278 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences