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Review reviewHigh

CVE-2026-64554

Linux

In the Linux kernel, the following vulnerability has been resolved: netfilter: bridge: fix stale prevhdr pointer in br_ip6_fragment() br_ip6_fragment() gets prevhdr, a pointer into the skb head, from ip6_find_1stfragopt(), then calls skb_checksum_help(). For a cloned skb skb_checksum_help() reallocates the head via pskb_expand_head(), leaving prevhdr dangling. It is later dereferenced in ip6_frag_next(), causing a use-after-free write. Save prevhdr's offset before skb_checksum_help() and recompute it after, like commit ef0efcd3bd3f ("ipv6: Fix dangling pointer when ipv6 fragment"). BUG: KAS...

CVSS
8.8
EPSS
-
- percentile
CISA KEV
Not listed
Published
2026.07.28
PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV
Exploit probability-
Technical severityCVSS 8.8

Vulnerability overview

In the Linux kernel, the following vulnerability has been resolved: netfilter: bridge: fix stale prevhdr pointer in br_ip6_fragment() br_ip6_fragment() gets prevhdr, a pointer into the skb head, from ip6_find_1stfragopt(), then calls skb_checksum_help(). For a cloned skb skb_checksum_help() reallocates the head via pskb_expand_head(), leaving prevhdr dangling. It is later dereferenced in ip6_frag_next(), causing a use-after-free write. Save prevhdr's offset before skb_checksum_help() and recompute it after, like commit ef0efcd3bd3f ("ipv6: Fix dangling pointer when ipv6 fragment"). BUG: KAS...

Affected product and versions

Product
Linux
Affected versions
>= 764dd163ac922f8683b5bcd3007251ce7b26cd33 < 8c10778ec674b67a07ea042fcba64270f3f38a5a, >= 764dd163ac922f8683b5bcd3007251ce7b26cd33 < 2731efa6364e47934c96eb69e01ea131e8af8030, >= 764dd163ac922f8683b5bcd3007251ce7b26cd33 < 00c06ef8c018493943891a7d0ca82b71b24f3180, >= 764dd163ac922f8683b5bcd3007251ce7b26cd33 < c141f69d0a0fb16964dbc293650047e69bda8af7, >= 764dd163ac922f8683b5bcd3007251ce7b26cd33 < f2e6596d10783557aeb9668da2a3b4d19deb2001, >= 764dd163ac922f8683b5bcd3007251ce7b26cd33 < 1c4f67c89fd27c4df4c70b135c2c59627698b3c0, >= 764dd163ac922f8683b5bcd3007251ce7b26cd33 < 4ac981a8b7ce7aec99a52d08f8a8953e8e120067, >= 764dd163ac922f8683b5bcd3007251ce7b26cd33 < 86f3ce81dd2b4b0aa2c3016c989a943e4b1b643d, >= 5.3
Fixed versions
No verified fixed-version field is available yet

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide
  1. 1
    Identify

    Confirm that 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:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CWE
Not available