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Review reviewHigh

CVE-2021-47291

Linux Linux, linux kernel

In the Linux kernel, the following vulnerability has been resolved: ipv6: fix another slab-out-of-bounds in fib6_nh_flush_exceptions While running the self-tests on a KASAN enabled kernel, I observed a slab-out-of-bounds splat very similar to the one reported in commit 821bbf79fe46 ("ipv6: Fix KASAN: slab-out-of-bounds Read in fib6_nh_flush_exceptions"). We additionally need to take care of fib6_metrics initialization failure when the caller provides an nh. The fix is similar, explicitly free the route instead of calling fib6_info_release on a half-initialized object.

CVSS
7.1
EPSS
0.25%
16.0% percentile
CISA KEV
Not listed
Published
2024.05.22
PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV
Exploit probability0.25%
Technical severityCVSS 7.1

Vulnerability overview

In the Linux kernel, the following vulnerability has been resolved: ipv6: fix another slab-out-of-bounds in fib6_nh_flush_exceptions While running the self-tests on a KASAN enabled kernel, I observed a slab-out-of-bounds splat very similar to the one reported in commit 821bbf79fe46 ("ipv6: Fix KASAN: slab-out-of-bounds Read in fib6_nh_flush_exceptions"). We additionally need to take care of fib6_metrics initialization failure when the caller provides an nh. The fix is similar, explicitly free the route instead of calling fib6_info_release on a half-initialized object.

Affected product and versions

Product
Linux Linux, linux kernel
Affected versions
>= f88d8ea67fbdbac7a64bfa6ed9a2ba27bb822f74 < 830251361425c5be044db4d826aaf304ea3d14c6, >= f88d8ea67fbdbac7a64bfa6ed9a2ba27bb822f74 < ce8fafb68051fba52546f8bbe8621f7641683680, >= f88d8ea67fbdbac7a64bfa6ed9a2ba27bb822f74 < 115784bcccf135c3a3548098153413d76f16aae0, >= f88d8ea67fbdbac7a64bfa6ed9a2ba27bb822f74 < 8fb4792f091e608a0a1d353dfdf07ef55a719db5, >= 5.3, >= 5.3 < 5.4.136, >= 5.5 < 5.10.54, >= 5.11 < 5.13.6, 5.14
Fixed versions
5.4.136, 5.10.54, 5.13.6

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide
  1. 1
    Identify

    Confirm that Linux Linux, linux kernel 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
CVE-2021-47291 — Linux Linux, linux kernel | SECUFOCUS NOW