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netfilter: nf_conntrack_h323: fix OOB read in decode_choice() (Linux Linux)

CVE-2026-43233
HIGH 8.2

At a glance

Source
NVD
EPSS
EPSS 0.46 % · percentile 40 ()
State
PUBLISHED
Published
Updated
Assigner
Linux
NVD status
Modified

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Description

In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_conntrack_h323: fix OOB read in decode_choice() In decode_choice(), the boundary check before get_len() uses the variable `len`, which is still 0 from its initialization at the top of the function: unsigned int type, ext, len = 0; ... if (ext || (son->attr & OPEN)) { BYTE_ALIGN(bs); if (nf_h323_error_boundary(bs, len, 0)) /* len is 0 here */ return H323_ERROR_BOUND; len = get_len(bs); /* OOB read */ When the bitstream is exactly consumed (bs->cur == bs->end), the check nf_h323_error_boundary(bs, 0, 0) evaluates to (bs->cur + 0 > bs->end), which is false. The subsequent get_len() call then dereferences *bs->cur++, reading 1 byte past the end of the buffer. If that byte has bit 7 set, get_len() reads a second byte as well. This can be triggered remotely by sending a crafted Q.931 SETUP message with a User-User Information Element containing exactly 2 bytes of PER-encoded data ({0x08, 0x00}) to port 1720 through a firewall with the nf_conntrack_h323 helper active. The decoder fully consumes the PER buffer before reaching this code path, resulting in a 1-2 byte heap-buffer-overflow read confirmed by AddressSanitizer. Fix this by checking for 2 bytes (the maximum that get_len() may read) instead of the uninitialized `len`. This matches the pattern used at every other get_len() call site in the same file, where the caller checks for 2 bytes of available data before calling get_len().

Weaknesses (CWE)

References

Scores

VersionScoreVectorScored by
CVSS 3.1HIGH 8.2CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:HLinux
CVSS 3.1HIGH 8.2CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:HNVD · 416baaa9-dc9f-4396-8d5f-8c081fb06d67 (Secondary)

European references

CERT-FR advisories

Affected configurations (NVD CPE)

Affected products

ProductVersions
Linux · Linuxaffected ec8a8f3c31ddef0a7d9626c4b8a4baa30f3b80aa < bcb50aa0b8f2b74a9fe5a1c7bee6f2657a288041 ; affected ec8a8f3c31ddef0a7d9626c4b8a4baa30f3b80aa < 2a3aac4205e7d2f1aca2e3827de8cdd517d36c4a ; affected ec8a8f3c31ddef0a7d9626c4b8a4baa30f3b80aa < 81f2fc5b0d0cf4696146f00f837596d10b92dead ; affected ec8a8f3c31ddef0a7d9626c4b8a4baa30f3b80aa < 7ef82863d42261817a6394c6c881bd6757a70f16 ; affected ec8a8f3c31ddef0a7d9626c4b8a4baa30f3b80aa < 53d32735d77ab56cc3fc7bd53a7d099418f19be1 ; affected ec8a8f3c31ddef0a7d9626c4b8a4baa30f3b80aa < f0a83d0a4b7c127d32ac06d607a9214937716129
Linux · Linuxaffected 4.15 ; unaffected 0 < 4.15 ; unaffected 5.10.252 ≤ 5.10.* ; unaffected 5.15.202 ≤ 5.15.* ; unaffected 6.1.165 ≤ 6.1.* ; unaffected 6.6.128 ≤ 6.6.*

Sources

SourceLicence
CVE List (CVEProject cvelistV5)CVE Program Terms of Use
EPSS (FIRST.org)FIRST — attribution requested
ENISA EUVDENISA — reproduction authorised, source acknowledged
CERT-FR (ANSSI)Licence Ouverte / Etalab 2.0
NVD (NIST) via fkie-cad/nvd-json-data-feedsPublic domain — this product uses data from the NVD API but is not endorsed or certified by the NVD