Bluetooth: L2CAP: validate option length before reading conf opt value
Published Jul 25, 2026
7.1
HIGHCVSS 3.1
EPSS 0.40%
Description
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.
Affected products
-
Affected
- ≥ , <
- ≥ , <
- ≥ , <
- ≥ , <
- ≥ , <
- ≥ , <
- ≥ , <
- ≥ , <
-
Affected
- ≥ 3.16.66, < 3.17
- ≥ 3.18.138, < 3.19
- ≥ 4.14.110, < 4.15
- ≥ 4.19.33, < 4.20
- ≥ 4.4.178, < 4.5
- ≥ 4.9.167, < 4.10
- ≥ 5.0.6, < 5.1
-
Affected
- 5.1
Unaffected
- ≥ 0, < 5.1
- ≥ 5.10.261, ≤ 5.10.*
- ≥ 5.15.212, ≤ 5.15.*
- ≥ 6.1.178, ≤ 6.1.*
- ≥ 6.12.96, ≤ 6.12.*
- ≥ 6.18.39, ≤ 6.18.*
- ≥ 6.6.145, ≤ 6.6.*
- ≥ 7.1.4, ≤ 7.1.*
- 7.2
Default status is the baseline for the product. Each version can override it (patched versions can be marked unaffected).
| Vendor | Product | Default status | Versions |
|---|---|---|---|
| Linux | Linux | unaffected | Affected
|
| Linux | Linux | unaffected | Affected
|
| Linux | Linux | affected | Affected
Unaffected
|
- ≥ 3.16.66 · < 3.17
- ≥ 3.18.138 · < 3.19
- ≥ 4.4.178 · < 4.5
- ≥ 4.9.167 · < 4.10
- ≥ 4.14.110 · < 4.15
- ≥ 4.19.33 · < 4.20
- ≥ 5.0.6 · < 5.10.261
- ≥ 5.11 · < 5.15.212
- ≥ 5.16 · < 6.1.178
- ≥ 6.2 · < 6.6.145
- ≥ 6.7 · < 6.12.96
- ≥ 6.13 · < 6.18.39
- ≥ 6.19 · < 7.1.4
- 7.2
- 7.2
No data.
Red Hat Enterprise Linux 10
kernel
Fix deferred
Red Hat Enterprise Linux 6
kernel
Not affected
Red Hat Enterprise Linux 7
kernel
Fix deferred
Red Hat Enterprise Linux 7
kernel-rt
Fix deferred
Red Hat Enterprise Linux 8
kernel
Fix deferred
Red Hat Enterprise Linux 8
kernel-rt
Fix deferred
Red Hat Enterprise Linux 9
kernel
Fix deferred
Red Hat Enterprise Linux 9
kernel-rt
Fix deferred
| Product | Package | State | Advisory |
|---|---|---|---|
| Red Hat Enterprise Linux 10 | kernel | Fix deferred | n/a |
| Red Hat Enterprise Linux 6 | kernel | Not affected | n/a |
| Red Hat Enterprise Linux 7 | kernel | Fix deferred | n/a |
| Red Hat Enterprise Linux 7 | kernel-rt | Fix deferred | n/a |
| Red Hat Enterprise Linux 8 | kernel | Fix deferred | n/a |
| Red Hat Enterprise Linux 8 | kernel-rt | Fix deferred | n/a |
| Red Hat Enterprise Linux 9 | kernel | Fix deferred | n/a |
| Red Hat Enterprise Linux 9 | kernel-rt | Fix deferred | n/a |
No package ranges for this CVE.
Remediation
No remediation recorded yet.
References (14)
- https://access.redhat.com/security/cve/CVE-2026-64403 Vendor Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=2507242 Issue Tracking
- https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-48947 Advisory
- https://git.kernel.org/stable/c/687617555cedfb74c9e3cb85d759b908dcb17856 Patch
- https://git.kernel.org/stable/c/6b47bdaacfd0045687880177e0987055d8f4765a Patch
- https://git.kernel.org/stable/c/73abbaf91aa33da87c008fb62c148ade561bb606 Patch
- https://git.kernel.org/stable/c/7d871e969b941ce25653f7716203a0ea4d07ad4b Patch
- https://git.kernel.org/stable/c/98d93c226bdfaa79bbdd86981921d7f106374225 Patch
- https://git.kernel.org/stable/c/996d3da39899aceb8f4910911a3f19a45a7d9d1b Patch
- https://git.kernel.org/stable/c/cca81b4bc672604a84f6d224a55cc77ec7dee619 Patch
- https://git.kernel.org/stable/c/f70d4aa88068096f35d73e3a05eff33c0a16b9cd Patch
- https://lore.kernel.org/linux-cve-announce/2026072530-CVE-2026-64403-31f1@gregkh/T
- https://nvd.nist.gov/vuln/detail/CVE-2026-64403
- https://www.cve.org/CVERecord?id=CVE-2026-64403
Change history (0)
No recorded changes yet.
CVE.org / MITRE
CISA Vulnrichment
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GitHub
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