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Critical 9.8Published Sep 16, 2026

CVE-2026-89783xfrm6: fix out-of-bounds write in xfrm6_input_addr() when secpath is full

Updated under an hour ago ()

Does this affect you?

It affects Linux. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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]'

CVSS
9.8 CRITICAL (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness (CWE)
Not given
Known exploited
Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days)
Not loaded for this CVE
Assigned by
Linux
NVD analysis
Received
Record last updated
Sep 16, 2026
First seen by InfoSec Signals
Oct 9, 2026

Affected products

Affected products
Linux Linux
linux:linux (from the name)
9473e1f631de339c50bde1e3bd09e1045fe90fd5 builds before 91fc387f63c00ddfb5221127a17bac97549a8343; 9473e1f631de339c50bde1e3bd09e1045fe90fd5 builds before 68e8737fe8e72f085c608cff322b3d2de8340af1; 9473e1f631de339c50bde1e3bd09e1045fe90fd5 builds before 8fe2c53fb81f5ad5be43af2ad09583f7c78b4b77; from 9473e1f631de339c50bde1e3bd09e1045fe90fd5 before bdcda866c89f9a8b1acdabf02d26cde9fbe501d8; from 9473e1f631de339c50bde1e3bd09e1045fe90fd5 before 48996649222e95008cdb98cd58579e3fc8e5ee06; 9473e1f631de339c50bde1e3bd09e1045fe90fd5 builds before 0f679e0523ddfff3fb554336ceb874b0e51e9cd3; 9473e1f631de339c50bde1e3bd09e1045fe90fd5 builds before 5f35a29a5eed3d80befd32050843ac88dea3d61a; 9473e1f631de339c50bde1e3bd09e1045fe90fd5 builds before 5d9e3bf34fec9a5d237e4b7cef4a707bc2e091bc
CNA record

References

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.

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