CVE-2026-89783

Critical

Description

In the Linux kernel, the following vulnerability has been resolved: xfrm6: fix out-of-bounds write in xfrm6_input_addr() when secpath is full The depth check in xfrm6_input_addr() is off by one: if (1 + sp->len == XFRM_MAX_DEPTH) goto drop; ... sp->xvec[sp->len++] = x; xfrm_input() can leave sp->len == XFRM_MAX_DEPTH, and the transport-mode receive path re-enters IPv6 input via xfrm_trans_reinject() with that secpath preserved. If the inner packet carries a destination-options HAO option or a type-2 routing header, xfrm6_input_addr() is called with sp->len == XFRM_MAX_DEPTH; the check (1 + 6 == 6) is false, so sp->xvec[sp->len++] writes one slot past the 6-element xvec[]. The write stays within the sec_path allocation (invisible to KASAN); UBSAN_BOUNDS flags it and panics under panic_on_warn. Use "sp->len >= XFRM_MAX_DEPTH", matching xfrm_input(). This also restores one chain level the old check rejected at sp->len == 5. UBSAN: array-index-out-of-bounds in net/ipv6/xfrm6_input.c:309:10 index 6 is out of range for type 'xfrm_state *[6]'

SeverityCritical
CVSS9.8
Exploit probability—
ProductLinux
PublishedSep 16, 2026
First seenSep 16, 2026

How to fix

Update
  • Linux Linux91fc387f63c00ddfb5221127a17bac97549a8343, 68e8737fe8e72f085c608cff322b3d2de8340af1, 8fe2c53fb81f5ad5be43af2ad09583f7c78b4b77, bdcda866c89f9a8b1acdabf02d26cde9fbe501d8, 48996649222e95008cdb98cd58579e3fc8e5ee06, 0f679e0523ddfff3fb554336ceb874b0e51e9cd3, 5f35a29a5eed3d80befd32050843ac88dea3d61a, 5d9e3bf34fec9a5d237e4b7cef4a707bc2e091bc or later

Affected products

ProductAffected versionsFixed in
Linux Linux9473e1f631de339c50bde1e3bd09e1045fe90fd5 ≤ v < 91fc387f63c00ddfb5221127a17bac97549a8343, 9473e1f631de339c50bde1e3bd09e1045fe90fd5 ≤ v < 68e8737fe8e72f085c608cff322b3d2de8340af1, 9473e1f631de339c50bde1e3bd09e1045fe90fd5 ≤ v < 8fe2c53fb81f5ad5be43af2ad09583f7c78b4b77, 9473e1f631de339c50bde1e3bd09e1045fe90fd5 ≤ v < bdcda866c89f9a8b1acdabf02d26cde9fbe501d8, 9473e1f631de339c50bde1e3bd09e1045fe90fd5 ≤ v < 48996649222e95008cdb98cd58579e3fc8e5ee06, 9473e1f631de339c50bde1e3bd09e1045fe90fd5 ≤ v < 0f679e0523ddfff3fb554336ceb874b0e51e9cd3, 9473e1f631de339c50bde1e3bd09e1045fe90fd5 ≤ v < 5f35a29a5eed3d80befd32050843ac88dea3d61a, 9473e1f631de339c50bde1e3bd09e1045fe90fd5 ≤ v < 5d9e3bf34fec9a5d237e4b7cef4a707bc2e091bc, 2.6.2591fc387f63c00ddfb5221127a17bac97549a8343, 68e8737fe8e72f085c608cff322b3d2de8340af1, 8fe2c53fb81f5ad5be43af2ad09583f7c78b4b77, bdcda866c89f9a8b1acdabf02d26cde9fbe501d8, 48996649222e95008cdb98cd58579e3fc8e5ee06, 0f679e0523ddfff3fb554336ceb874b0e51e9cd3, 5f35a29a5eed3d80befd32050843ac88dea3d61a, 5d9e3bf34fec9a5d237e4b7cef4a707bc2e091bc

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CVE-2026-89783 · Linux · Dark Radar