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CVE-2026-72020

ipvs: reset full ip_vs_seq structs in ip_vs_conn_new

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 5.10.261, 5.15.212, 6.1.178, 6.6.145, 6.12.97, and 2 more
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: none
  • Automatable: yes
  • Technical impact: total

Summary

In the Linux kernel, the following vulnerability has been resolved: ipvs: reset full ip_vs_seq structs in ip_vs_conn_new Commit 9a05475cebdd ("ipvs: avoid kmem_cache_zalloc in ip_vs_conn_new") changed ip_vs_conn_new() to allocate an ip_vs_conn object with kmem_cache_alloc(). The function then initializes many fields explicitly, but only resets in_seq.delta and out_seq.delta in the two struct ip_vs_seq members. That leaves init_seq and previous_delta uninitialized. This is normally harmless while the corresponding IP_VS_CONN_F_IN_SEQ or IP_VS_CONN_F_OUT_SEQ flag is clear. For connections learned from a sync message, however, ip_vs_proc_conn() preserves those flags from IP_VS_CONN_F_BACKUP_MASK and passes opt=NULL when the message omits IPVS_OPT_SEQ_DATA. In that case the new connection can be hashed with SEQ flags set but with the rest of in_seq/out_seq still containing stale slab data. When a packet for such a connection is later handled by an IPVS application helper, vs_fix_seq() and vs_fix_ack_seq() use previous_delta and init_seq to rewrite TCP sequence numbers. A malformed sync message can therefore make forwarded packets carry stale slab bytes in their TCP seq/ack numbers, and can also corrupt the forwarded TCP flow. Reset both struct ip_vs_seq members completely before publishing the connection. This matches the existing "reset struct ip_vs_seq" comment and keeps the sequence-adjustment gates inactive unless valid sequence data is installed later.

Timeline

  1. CVE published
  2. CISA SSVC assessment

    Exploitation: none · Automatable: yes · Technical impact: total

  3. Record last updated

Affected versions

  • Linux Linux

    From 9a05475cebdd6341884b5901e53870be26e65158 · fixed in 3bf9a260188b2a5449cbddc032a749ab433fe328; From 9a05475cebdd6341884b5901e53870be26e65158 · fixed in 6378c5cb360eb1750f88839d7c3613ea92ac1816; From 9a05475cebdd6341884b5901e53870be26e65158 · fixed in 32c299e28b8eea6cbbd23b97dc61401e9ef9c445; From 9a05475cebdd6341884b5901e53870be26e65158 · fixed in 9e36602cbec552286f7e691cfd366525c565ee74; From 9a05475cebdd6341884b5901e53870be26e65158 · fixed in d0eed7177e822cab83141e5c44b2aa345c7fd379; From 9a05475cebdd6341884b5901e53870be26e65158 · fixed in 83fb4c2c5344f02eac929f66de3c9d1adfcde04c; From 9a05475cebdd6341884b5901e53870be26e65158 · fixed in 6335ab62d5fc9ed875279238233fba3462c168f5; From 9a05475cebdd6341884b5901e53870be26e65158 · fixed in 2975324d164c552b028632f107b567302863b7f6

  • Linux Linux

    3.10

  • KernelLinux

    From 3.10.0 · fixed in 5.10.261; From 5.11.0 · fixed in 5.15.212; From 5.16.0 · fixed in 6.1.178; From 6.2.0 · fixed in 6.6.145; From 6.7.0 · fixed in 6.12.97; From 6.13.0 · fixed in 6.18.40; From 6.19.0 · fixed in 7.1.5

References 8

git.kernel.org