Bluetooth: L2CAP: validate option length before reading conf opt value
Key facts
- Attack vector
- Adjacent network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- Low · None · High
- Fix status
- Partial Red Hat: 4 without a fix
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat. Impact type from CWE-476.
Summary
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: L2CAP: validate option length before reading conf opt value l2cap_get_conf_opt() derives the option length from the attacker-controlled opt->len field and immediately dereferences opt->val (as u8, get_unaligned_le16() or get_unaligned_le32(), or a raw pointer for the default case) before any caller has confirmed that opt->len bytes are present in the buffer. The callers (l2cap_parse_conf_req(), l2cap_parse_conf_rsp() and l2cap_conf_rfc_get()) only detect a malformed option afterwards, once the running length has gone negative, by which point the out-of-bounds read has already executed. An existing post-hoc length check keeps the garbage value from being consumed, so this is not a data leak in the current control flow. It is still a validate-after-use ordering bug: up to 4 bytes are read past the end of the buffer before it is known to contain them, and it is fragile to future changes in the callers. Fix it at the source. Pass the end of the buffer into l2cap_get_conf_opt() and refuse to touch opt->val unless the full option (header + value) fits. Each caller computes an end pointer once before the loop and checks the return value directly instead of inferring the error from a negative length.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Linux | Linux | 3.16.66 to before 3.17; 3.18.138 to before 3.19; 4.4.178 to before 4.5; 4.9.167 to before 4.10; 4.14.110 to before 4.15; 4.19.33 to before 4.20; 5.0.6 to before 5.1 | 3.17, 3.19, 4.5, 4.10, 4.15, 4.20, 5.1 | Patch available | CNA |
| Linux | Linux | 5.1 and later | 5.10.261, 5.15.212, 6.1.178, 6.6.145, 6.12.96, 6.18.39, 7.1.4, 7.2 | Patch available | CNA |
- Linux VendorLinux Affected 3.16.66 to before 3.17; 3.18.138 to before 3.19; 4.4.178 to before 4.5; 4.9.167 to before 4.10; 4.14.110 to before 4.15; 4.19.33 to before 4.20; 5.0.6 to before 5.1 Fixed in 3.17, 3.19, 4.5, 4.10, 4.15, 4.20, 5.1 Patch available CNA
- Linux VendorLinux Affected 5.1 and later Fixed in 5.10.261, 5.15.212, 6.1.178, 6.6.145, 6.12.96, 6.18.39, 7.1.4, 7.2 Patch available CNA
CPE configurations NVD · 3
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | 3.16.66 to before 3.17; 3.18.138 to before 3.19; 4.4.178 to before 4.5; 4.9.167 to before 4.10; 4.14.110 to before 4.15; 4.19.33 to before 4.20; 5.0.6 to before 5.10.261; 5.11 to before 5.15.212; 5.16 to before 6.1.178; 6.2 to before 6.6.145; 6.7 to before 6.12.96; 6.13 to before 6.18.39; 6.19 to before 7.1.4 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:7.2:rc1:*:*:*:*:*:* | 7.2 rc1 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:7.2:rc2:*:*:*:*:*:* | 7.2 rc2 | Vulnerable | Linux |
- cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions 3.16.66 to before 3.17; 3.18.138 to before 3.19; 4.4.178 to before 4.5; 4.9.167 to before 4.10; 4.14.110 to before 4.15; 4.19.33 to before 4.20; 5.0.6 to before 5.10.261; 5.11 to before 5.15.212; 5.16 to before 6.1.178; 6.2 to before 6.6.145; 6.7 to before 6.12.96; 6.13 to before 6.18.39; 6.19 to before 7.1.4 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:7.2:rc1:*:*:*:*:*:* Versions 7.2 rc1 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:7.2:rc2:*:*:*:*:*:* Versions 7.2 rc2 Vulnerable ·Linux
Remediation
- Fix · CNA Linux (Linux) Fixed in 3.17, 3.19, 4.5, 4.10, 4.15, 4.20, 5.1
- Fix · CNA Linux (Linux) Fixed in 5.10.261, 5.15.212, 6.1.178, 6.6.145, 6.12.96, 6.18.39, 7.1.4, 7.2
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 7 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 8 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
Not affected: 1 product
- Red Hat Enterprise Linux 6
Timeline
- 2026-10-02 Threatist record created from CVE-2026-64403
- 2026-10-03 Alias added: GHSA-wqwg-v9cc-cpq7
- 2026-10-16 CISA SSVC decision points changed
- 2026-10-20 Weakness changed · CISA ADP
- 2026-10-27 CVSS score changed · Red Hat
References
Patch 8
- https://git.kernel.org/stable/c/cca81b4bc672604a84f6d224a55cc77ec7dee619
- https://git.kernel.org/stable/c/f70d4aa88068096f35d73e3a05eff33c0a16b9cd
- https://git.kernel.org/stable/c/7d871e969b941ce25653f7716203a0ea4d07ad4b
- https://git.kernel.org/stable/c/98d93c226bdfaa79bbdd86981921d7f106374225
- https://git.kernel.org/stable/c/996d3da39899aceb8f4910911a3f19a45a7d9d1b
- https://git.kernel.org/stable/c/73abbaf91aa33da87c008fb62c148ade561bb606
- https://git.kernel.org/stable/c/6b47bdaacfd0045687880177e0987055d8f4765a
- https://git.kernel.org/stable/c/687617555cedfb74c9e3cb85d759b908dcb17856
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Sources
- CVE-2026-64403 · CVE Program
- CVE-2026-64403 · NVD
- FIRST EPSS
- GHSA-wqwg-v9cc-cpq7 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-64403 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences