What is CVE-2026-89783?

CVE-2026-89783 is a Critical severity Linux kernel vulnerability with a CVSS score of 9.8 out of 10, affecting Linux kernel versions from 2.6.25 onward and patched in 5.10.270, 5.15.221, 6.1.188 and others. CVE-2026-89783 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2026-89783?

CVE-2026-89783 has a CVSS score of 9.8 out of 10, rated Critical severity. The vector string is CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Is there a patch available for CVE-2026-89783?

Yes, CVE-2026-89783 has been patched. Fixed versions include 5.10.270, 5.15.221, 6.1.188 and others. If you are running Linux kernel 2.6.25 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2026-89783 actively exploited?

CVE-2026-89783 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

CVE-2026-89783

Critical

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]'

Package Linux Kernel

Published 2026-09-16

Last modified 2026-09-16

CVSS version 3.1

Patch available

Yes

CVSS 3.1 score

9.8

out of 10

Critical

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Vector string

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected versions

Linux kernel versions 2.6.25 and later are affected. Fixed in 5.10.270, 5.15.221, 6.1.188, 6.6.157, 6.12.110, 6.18.52, 7.2.6, 7.3-rc1 and their respective stable series.

Affected from

≥ 2.6.25

Fixed in

✓ 5.10.270 5.10.x ✓ 5.15.221 5.15.x ✓ 6.1.188 6.1.x ✓ 6.6.157 6.6.x ✓ 6.12.110 6.12.x ✓ 6.18.52 6.18.x ✓ 7.2.6 7.2.x ✓ 7.3-rc1

References

8 total

Showing 5 of 8 references View all on NVD

Details

CVE ID CVE-2026-89783

Severity Critical

CVSS score 9.8 / 10

CVSS version 3.1

Published 2026-09-16

Modified 2026-09-16

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2026-89783?

CVE-2026-89783 is a Critical severity Linux kernel vulnerability with a CVSS score of 9.8 out of 10 . It affects Linux kernel versions from 2.6.25 onward and has been patched in 5.10.270, 5.15.221, 6.1.188 and others. CVE-2026-89783 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2026-89783?

CVE-2026-89783 has a CVSS score of 9.8 out of 10, rated Critical severity (CVSS 3.1). The vector string is CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
Is there a patch available for CVE-2026-89783?

Yes. CVE-2026-89783 has been patched. Fixed versions include 5.10.270, 5.15.221, 6.1.188 and others. If you are running Linux kernel 2.6.25 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2026-89783 actively exploited?

No. CVE-2026-89783 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.