CVE-2026-23456
CVE-2026-23456 is a high-severity vulnerability in Linux Linux Kernel with a CVSS 3.x base score of 8.2. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-125.
Key facts
- Severity: High (CVSS 3.x base score 8.2)
- EPSS exploit prediction: 0% (36th percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2026-18712
- Weakness: CWE-125
- Affected product: Linux Linux Kernel
- Published:
- Last modified:
Description
In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_conntrack_h323: fix OOB read in decode_int() CONS case In decode_int(), the CONS case calls get_bits(bs, 2) to read a length value, then calls get_uint(bs, len) without checking that len bytes remain in the buffer. The existing boundary check only validates the 2 bits for get_bits(), not the subsequent 1-4 bytes that get_uint() reads. This allows a malformed H.323/RAS packet to cause a 1-4 byte slab-out-of-bounds read. Add a boundary check for len bytes after get_bits() and before get_uint().
Frequently asked questions
- What is CVE-2026-23456?
- In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_conntrack_h323: fix OOB read in decode_int() CONS case In decode_int(), the CONS case calls get_bits(bs, 2) to read a length value, then calls get_uint(bs, len) without checking that len bytes remain in the buffer. The existing boundary check only validates the 2 bits for get_bits(), not the subsequent 1-4 bytes that get_uint() reads. This allows a malformed H.323/RAS packet to cause a 1-4 byte slab-out-of-bounds read. Add a boundary check for len bytes after get_bits() and before get_uint().
- How severe is CVE-2026-23456?
- CVE-2026-23456 has a CVSS 3.x base score of 8.2, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability high.
- Is CVE-2026-23456 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (36th percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2026-23456?
- CVE-2026-23456 primarily affects Linux Linux Kernel. In total, 5 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
- How do I fix CVE-2026-23456?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
- Does CVE-2026-23456 have an EU (EUVD) identifier?
- Yes. CVE-2026-23456 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-18712.
- When was CVE-2026-23456 published?
- CVE-2026-23456 was published on 2026-04-03 and last updated on 2026-06-17.
References
- https://git.kernel.org/stable/c/1e3a3593162c96e8a8de48b1e14f60c3b57fca8a
- https://git.kernel.org/stable/c/41b417ff73a24b2c68134992cc44c88db27f482d
- https://git.kernel.org/stable/c/52235bf88159a1ef16434ab49e47e99c8a09ab20
- https://git.kernel.org/stable/c/6bce72daeccca9aa1746e92d6c3d4784e71f2ebb
- https://git.kernel.org/stable/c/774a434f8c9c8602a976b2536f65d0172a07f4d2
- https://git.kernel.org/stable/c/a2cd54b9348e485d338b3c132338a4410c99afaf
- https://git.kernel.org/stable/c/c95dc674ebf01ecfb40388b6facfc89b81fed3b7
- https://git.kernel.org/stable/c/fb6c3596823ec5dd09c2123340330d7448f51a59
Affected products (5)
- cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
- cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:*
- cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:*
- cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:*
- cpe:2.3:o:linux:linux_kernel:7.0:rc4:*:*:*:*:*:*
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