CVE-2026-23456: netfilter: nf_conntrack_h323: fix OOB read in decode_int() CONS case
Vulnerability summary
CVE-2026-23456 is a high (CVSS 8.2) Out-of-bounds Read vulnerability in linux. EPSS estimates a 0.54% chance of exploitation in the next 30 days, higher than 45.6% of scored vulnerabilities.
Severe, CVSS 8.2 (CVE.org); no exploitation reported by the 5 checked sources; EPSS 1% (FIRST, 03-11-2026)
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 29 · Related 29Timeline
- 03-04-2026PublishedVulnerability first disclosed.
- 19-10-2026Last modifiedVulnerability information updated.
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().
CVSS metrics
5 scores · 4 sources · 2 versions- OSV · UbuntuEcosystem advisory · calculated8.2HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H
- OSV · DebianEcosystem advisory · calculated8.2HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H
- NVDNIST8.2HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H
EPSS trend
Probability
0.54%
Chance of exploitation in the next 30 days
Percentile
46%
Versus all other CVEs
30-day change
Increase +0.02 pp
From 0.52% on 04-10-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.
Ubuntu157 products
- linuxAll versions (No fix recorded) | < 5.15.0-186.196 | < 6.8.0-136.136
- linux-allwinner-5.19All versions (No fix recorded)
- linux-awsAll versions (No fix recorded) | < 5.15.0-1112.119 | < 6.8.0-1061.64
- linux-aws-5.0All versions (No fix recorded)
- linux-aws-5.11All versions (No fix recorded)
Linux2 products
- linux≥ 5e35941d990123f155b02d5663e51a24f816b6f3, < a2cd54b9348e485d338b3c132338a4410c99afaf | ≥ 5e35941d990123f155b02d5663e51a24f816b6f3, < c95dc674ebf01ecfb40388b6facfc89b81fed3b7 | ≥ 5e35941d990123f155b02d5663e51a24f816b6f3, < 41b417ff73a24b2c68134992cc44c88db27f482d | ≥ 5e35941d990123f155b02d5663e51a24f816b6f3, < 52235bf88159a1ef16434ab49e47e99c8a09ab20 | ≥ 5e35941d990123f155b02d5663e51a24f816b6f3, < 774a434f8c9c8602a976b2536f65d0172a07f4d2 | ≥ 5e35941d990123f155b02d5663e51a24f816b6f3, < 6bce72daeccca9aa1746e92d6c3d4784e71f2ebb | ≥ 5e35941d990123f155b02d5663e51a24f816b6f3, < fb6c3596823ec5dd09c2123340330d7448f51a59 | ≥ 5e35941d990123f155b02d5663e51a24f816b6f3, < 1e3a3593162c96e8a8de48b1e14f60c3b57fca8a | 2.6.17
- linux_kernel≥ 2.6.17, < 5.10.253 | ≥ 5.11, < 5.15.203 | ≥ 5.16, < 6.1.167 | ≥ 6.2, < 6.6.130 | ≥ 6.7, < 6.12.78 | ≥ 6.13, < 6.18.20 | ≥ 6.19, < 6.19.10 | 7.0:rc1 | 7.0:rc2 | 7.0:rc3 | 7.0:rc4
Debian1 product
- linux< 6.1.170-1 | < 6.12.85-1 | < 6.19.10-1
3 vendors · 160 products
