sch_htb: make htb_deactivate() idempotent (Linux Linux)
At a glance
- Source
- NVD
- EPSS
- EPSS 0.19 % · percentile 9 ()
- State
- PUBLISHED
- Published
- Updated
- Assigner
- Linux
- NVD status
- Analyzed
Description
In the Linux kernel, the following vulnerability has been resolved: sch_htb: make htb_deactivate() idempotent Alan reported a NULL pointer dereference in htb_next_rb_node() after we made htb_qlen_notify() idempotent. It turns out in the following case it introduced some regression: htb_dequeue_tree(): |-> fq_codel_dequeue() |-> qdisc_tree_reduce_backlog() |-> htb_qlen_notify() |-> htb_deactivate() |-> htb_next_rb_node() |-> htb_deactivate() For htb_next_rb_node(), after calling the 1st htb_deactivate(), the clprio[prio]->ptr could be already set to NULL, which means htb_next_rb_node() is vulnerable here. For htb_deactivate(), although we checked qlen before calling it, in case of qlen==0 after qdisc_tree_reduce_backlog(), we may call it again which triggers the warning inside. To fix the issues here, we need to: 1) Make htb_deactivate() idempotent, that is, simply return if we already call it before. 2) Make htb_next_rb_node() safe against ptr==NULL. Many thanks to Alan for testing and for the reproducer.
Weaknesses (CWE)
- CWE-476 — NULL Pointer Dereference
References
- https://git.kernel.org/stable/c/99ff8a20fd61315bf9ae627440a5ff07d22ee153
- https://git.kernel.org/stable/c/a9945f7cf1709adc5d2d31cb6cfc85627ce299a8
- https://git.kernel.org/stable/c/c2d25fddd867ce20a266806634eeeb5c30cb520c
- https://git.kernel.org/stable/c/c928dd4f6bf0c25c72b11824a1e9ac9bd37296a0
- https://git.kernel.org/stable/c/31ff70ad39485698cf779f2078132d80b57f6c07
- https://git.kernel.org/stable/c/98cd7ed92753090a714f0802d4434314526fe61d
- https://git.kernel.org/stable/c/c4792b9e38d2f61b07eac72f10909fa76130314b
- https://git.kernel.org/stable/c/3769478610135e82b262640252d90f6efb05be71
- https://lists.debian.org/debian-lts-announce/2025/08/msg00010.html
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 3.1 | MEDIUM 5.5 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H | NVD · nvd@nist.gov (Primary) |
European references
- ENISA EUVD · EUVD-2025-15902
- GCVE · GCVE-0-2025-37953
CERT-FR advisories
- CERTFR-2026-AVI-0081 — Multiples vulnérabilités dans le noyau Linux de SUSE · cert.ssi.gouv.fr
- CERTFR-2025-AVI-1009 — Multiples vulnérabilités dans le noyau Linux de SUSE · cert.ssi.gouv.fr
- CERTFR-2025-AVI-0723 — Multiples vulnérabilités dans le noyau Linux de SUSE · cert.ssi.gouv.fr
- CERTFR-2025-AVI-0697 — Multiples vulnérabilités dans le noyau Linux de Debian LTS · cert.ssi.gouv.fr
- CERTFR-2025-AVI-0649 — Multiples vulnérabilités dans le noyau Linux de SUSE · cert.ssi.gouv.fr
- CERTFR-2025-AVI-0607 — Multiples vulnérabilités dans le noyau Linux de SUSE · cert.ssi.gouv.fr
- CERTFR-2025-AVI-0587 — Multiples vulnérabilités dans le noyau Linux de SUSE · cert.ssi.gouv.fr
- CERTFR-2025-AVI-0529 — Multiples vulnérabilités dans le noyau Linux de SUSE · cert.ssi.gouv.fr
- CERTFR-2025-AVI-0464 — Multiples vulnérabilités dans le noyau Linux de Debian · cert.ssi.gouv.fr
Affected configurations (NVD CPE)
cpe:2.3:o:linux:linux_kernel:6.1.138:*:*:*:*:*:*:*cpe:2.3:o:linux:linux_kernel:6.6.90:*:*:*:*:*:*:*cpe:2.3:o:linux:linux_kernel:6.12.28:*:*:*:*:*:*:*cpe:2.3:o:linux:linux_kernel:6.14.6:*:*:*:*:*:*:*cpe:2.3:o:linux:linux_kernel:6.15:rc2:*:*:*:*:*:*cpe:2.3:o:linux:linux_kernel:6.15:rc3:*:*:*:*:*:*cpe:2.3:o:linux:linux_kernel:6.15:rc4:*:*:*:*:*:*cpe:2.3:o:linux:linux_kernel:6.15:rc5:*:*:*:*:*:*cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*
Affected products
| Product | Versions |
|---|---|
| Linux · Linux | affected e6b45f4de763b00dc1c55e685e2dd1aaf525d3c1 < 99ff8a20fd61315bf9ae627440a5ff07d22ee153 ; affected 32ae12ce6a9f6bace186ca7335220ff59b6cc3cd < a9945f7cf1709adc5d2d31cb6cfc85627ce299a8 ; affected 967955c9e57f8eebfccc298037d4aaf3d42bc1c9 < c2d25fddd867ce20a266806634eeeb5c30cb520c ; affected 73cf6af13153d62f9b76eff422eea79dbc70f15e < c928dd4f6bf0c25c72b11824a1e9ac9bd37296a0 ; affected bbbf5e0f87078b715e7a665d662a2c0e77f044ae < 31ff70ad39485698cf779f2078132d80b57f6c07 ; affected 0a188c0e197383683fd093ab1ea6ce9a5869a6ea < 98cd7ed92753090a714f0802d4434314526fe61d |
| Linux · Linux | affected 6.1.138 < 6.1.139 ; affected 6.6.90 < 6.6.91 ; affected 6.12.28 < 6.12.29 ; affected 6.14.6 < 6.14.7 |
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| CERT-FR (ANSSI) | Licence Ouverte / Etalab 2.0 |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |