Out-of-Bounds Read in Linux kernel (CVE-2026-31513)
Summary
Vulnerability in Linux kernel (CVE-2026-31513). Confidential information can be exposed externally. Exploitable via pdu.
Original description
The description as published by the source.
In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: L2CAP: Fix stack-out-of-bounds read in l2cap_ecred_conn_req
Syzbot reported a KASAN stack-out-of-bounds read in l2cap_build_cmd()
that is triggered by a malformed Enhanced Credit Based Connection Request.
The vulnerability stems from l2cap_ecred_conn_req(). The function allocates
a local stack buffer (pdu) designed to hold a maximum of 5 Source Channel
IDs (SCIDs), totaling 18 bytes. When an attacker sends a request with more
than 5 SCIDs, the function calculates rsp_len based on this unvalidated
cmd_len before checking if the number of SCIDs exceeds
L2CAP_ECRED_MAX_CID.
If the SCID count is too high, the function correctly jumps to the
response label to reject the packet, but rsp_len retains the
attacker's oversized value. Consequently, l2cap_send_cmd() is instructed
to read past the end of the 18-byte pdu buffer, triggering a
KASAN panic.
Fix this by moving the assignment of rsp_len to after the num_scid
boundary check. If the packet is rejected, rsp_len will safely
remain 0, and the error response will only read the 8-byte base header
from the stack.
Source: NIST National Vulnerability Database NVD
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-31513 has been found in Linux kernel.
Attackers can target a specific entry point like pdu over the network to misuse the product.
Confidential information can be exposed externally. CVSS score: 8.1/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Linux kernel CVE-2026-31513" on the vendor's site.
CVE-2026-31513 (Linux kernel) — CWE-125 / CVSS v3 8.1
Attack vector: adjacent-network / unauthenticated / no user interaction
Attack surface: pdu / rsp_len / cmd_len / response
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
Out-of-bounds read (CWE-125) exists in Linux kernel. Attackers reach the vulnerable code path via pdu without authentication.
Check the vendor advisory for the affected versions of Linux kernel. Attack surface: pdu / rsp_len / cmd_len / response.
Severity: High (CVSS 8.1/10). Confidential information can be exposed externally.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Audit SBOM/dependencies to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
Audit SBOM/dependencies for affected components.資産台帳・SBOM・依存マニフェストで Linux kernel を使っているサービスとバージョンを洗い出す。
-
2Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Fix status by distribution
Fixed packages published by each distribution for this CVE
- BellSoft Alpaquita BELL-CVE-2026-31513 linux-lts Fixed in: 6.12.80-r0
- Debian DEBIAN-CVE-2026-31513 linux Fixed in: 6.19.11-1
- Ubuntu UBUNTU-CVE-2026-31513 linux-hwe-edge
References
- patch git.kernel.org
- patch git.kernel.org
- patch git.kernel.org
- patch git.kernel.org