CVE-2026-98085

bpf: backtrack_insn(): Handle ld_{abs,ind} subprog exit edge

Published Sep 25, 2026 CVSS n/a EPSS < 1% KEV · Not listed

Description

In the Linux kernel, the following vulnerability has been resolved:

bpf: backtrack_insn(): Handle ld_{abs,ind} subprog exit edge

Nicholas Carlini reported a bug in precision backtracking mechanism
for BPF_LD | BPF_{IND,ABS} instructions. These instructions are
modelled as two branches:
- fallthrough;
- implicit exit from current subprogram.

The implicit exit case was not handled by the backtrack_insn()
function. When backtracking such a path backtrack_insn() did not
call bt_subprog_enter(), which meant that backtracking continued
manipulating precision marks in a caller frame, while looking at
instructions in a callee frame.

This lead to segmentation faults during verification (see the
selftest), or unsound state pruning.

Affected Products

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

Linux

unaffected

Version	Status	Constraints
`37ad2bb11e9de92cb7b94548705eeedd87f7d392`	affected	< 19cca7c36055906b3cff3e297618ee8a50cde25d
`8674e2db06cff6b50f2216eed9a761d15425bb34`	affected	< 12c064bcfa56e3631be9f5336ee113b7f849959a
`ce01a4e5cfac7adbe0be565f90cd32ecbb2f8337`	affected	< a0cd9e22f8faed30a8da8be357c51bd8b3074ee9
`ee861486e377edc55361c08dcbceab3f6b6577bd`	affected	< 671b7b9a660ef15b25faa3df161205b9dc8d1eb2
`ee861486e377edc55361c08dcbceab3f6b6577bd`	affected	< 387b1baefbb776e3f48dc2261e77a49213f470f7
`928d354ae3557e8f755a227e67be88034eb3cd7f`	affected	—
`8a800497d9f6c2ec9c2c1ba7b71d0ac2ea7f7bbe`	affected	—
`de1055e7f9e67af32b1f3376066272b04e5223c0`	affected	—
`d846d83bdacbd8f14fc45c63b8c1d22608452e1c`	affected	—
`6.6.148`	affected	< 6.6.160
`6.12.101`	affected	< 6.12.114
`6.18.42`	affected	< 6.18.57
`5.10.265`	affected	< 5.11
`5.15.216`	affected	< 5.16
`6.1.183`	affected	< 6.2
`7.0.10`	affected	< 7.1

Linux

affected

Version	Status	Constraints
`7.1`	affected	—
`0`	unaffected	< 7.1
`6.6.160`	unaffected	≤ 6.6.*
`6.12.114`	unaffected	≤ 6.12.*
`6.18.57`	unaffected	≤ 6.18.*
`7.2.7`	unaffected	≤ 7.2.*
`7.3`	unaffected	≤ *

No data.

Vendor Product Versions

Linux

Linux Kernel

Version	Status	Scheme	Platform
`[ee861486e377edc55361c08dcbceab3f6b6577bd,671b7b9a660ef15b25faa3df161205b9dc8d1eb2)`	affected	code_commit	—
`[ee861486e377edc55361c08dcbceab3f6b6577bd,387b1baefbb776e3f48dc2261e77a49213f470f7)`	affected	code_commit	—
`928d354ae3557e8f755a227e67be88034eb3cd7f`	affected	code_commit	—
`8a800497d9f6c2ec9c1ba7b71d0ac2ea7f7bbe`	affected	code_commit	—
`de1055e7f9e67af32b1f3376066272b04e5223c0`	affected	code_commit	—
`37ad2bb11e9de92cb7b94548705eeedd87f7d392`	affected	code_commit	—
`8674e2db06cff6b50f2216eed9a761d15425bb34`	affected	code_commit	—
`ce01a4e5cfac7adbe0be565f90cd32ecbb2f8337`	affected	code_commit	—
`d846d83bdacbd8f14fc45c63b8c1d22608452e1c`	affected	code_commit	—
`[5.10.265,5.11.0)`	affected	semver	—
`[5.15.216,5.16.0)`	affected	semver	—
`[6.1.183,6.2.0)`	affected	semver	—
`[6.6.148,6.7.0)`	affected	semver	—
`[6.12.101,6.13.0)`	affected	semver	—
`[6.18.42,6.19.0)`	affected	semver	—
`[7.0.10,7.1.0)`	affected	semver	—

Linux

Linux Kernel

Version	Status	Scheme	Platform
`7.1.0`	affected	semver	—
`[0,7.1.0)`	unaffected	semver	—
`[7.2.7,7.2.*]`	unaffected	generic	—
`[7.3-rc2,*]`	unaffected	generic	—

Remediation

No solution or workaround provided in the CVE record

Tracking

Advisories

Source	ID	Title
Debian DLA	DLA-4904-1	linux-6.12 security update
Ubuntu USN	USN-9019-1	Linux kernel (Azure) vulnerabilities
Ubuntu USN	USN-9020-1	Linux kernel vulnerabilities

Metrics

No CVSS v4.0

No CVSS v3.1

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploit prediction score: < 1% (0.200% probability within 30 days)

Key SSVC decision points have not yet been added.

References

Link	Providers
https://git.kernel.org/stable/c/12c064bcfa56e3631be9f5336ee113b7f849959a
https://git.kernel.org/stable/c/19cca7c36055906b3cff3e297618ee8a50cde25d
https://git.kernel.org/stable/c/387b1baefbb776e3f48dc2261e77a49213f470f7
https://git.kernel.org/stable/c/671b7b9a660ef15b25faa3df161205b9dc8d1eb2
https://git.kernel.org/stable/c/a0cd9e22f8faed30a8da8be357c51bd8b3074ee9

History

Oct 21, 2026 1:15 PM Added references View changes

Type	Values Removed	Values Added
References		https://git.kernel.org/stable/c/12c064bcfa56e3631be9f5336ee113b7f849959a https://git.kernel.org/stable/c/19cca7c36055906b3cff3e297618ee8a50cde25d

Oct 15, 2026 1:30 PM Added references View changes

Type	Values Removed	Values Added
References		https://git.kernel.org/stable/c/a0cd9e22f8faed30a8da8be357c51bd8b3074ee9

Sep 25, 2026 5:15 PM Weaknesses updated View changes

Type	Values Removed	Values Added
Weaknesses		CWE-119

Sep 25, 2026 10:30 AM Description updated. Title updated. First appearance in the feed. Affected versions updated. Affected vendors updated. Added references View changes

Type	Values Removed	Values Added
Description		In the Linux kernel, the following vulnerability has been resolved: bpf: backtrack_insn(): Handle ld_{abs,ind} subprog exit edge Nicholas Carlini reported a bug in precision backtracking mechanism for BPF_LD \| BPF_{IND,ABS} instructions. These instructions are modelled as two branches: - fallthrough; - implicit exit from current subprogram. The implicit exit case was not handled by the backtrack_insn() function. When backtracking such a path backtrack_insn() did not call bt_subprog_enter(), which meant that backtracking continued manipulating precision marks in a caller frame, while looking at instructions in a callee frame. This lead to segmentation faults during verification (see the selftest), or unsound state pruning.
Title		bpf: backtrack_insn(): Handle ld_{abs,ind} subprog exit edge
First Time appeared		Linux Linux linux Kernel
CPEs		cpe:2.3:o:linux:linux_kernel::::::::
Vendors & Products		Linux Linux linux Kernel
References		https://git.kernel.org/stable/c/387b1baefbb776e3f48dc2261e77a49213f470f7 https://git.kernel.org/stable/c/671b7b9a660ef15b25faa3df161205b9dc8d1eb2