netfilter: nf_conntrack_h323: fix OOB read in decode_choice()
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().
CVE-2026-43233
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-43233
Linux
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Linux
Source reference: /containers/cna/affected/1/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "ec8a8f3c31ddef0a7d9626c4b8a4baa30f3b80aa",
"lessThan": "bcb50aa0b8f2b74a9fe5a1c7bee6f2657a288041",
"versionType": "git"
},
{
"status": "affected",
"version": "ec8a8f3c31ddef0a7d9626c4b8a4baa30f3b80aa",
"lessThan": "2a3aac4205e7d2f1aca2e3827de8cdd517d36c4a",
"versionType": "git"
},
{
"status": "affected",
"version": "ec8a8f3c31ddef0a7d9626c4b8a4baa30f3b80aa",
"lessThan": "81f2fc5b0d0cf4696146f00f837596d10b92dead",
"versionType": "git"
},
{
"status": "affected",
"version": "ec8a8f3c31ddef0a7d9626c4b8a4baa30f3b80aa",
"lessThan": "7ef82863d42261817a6394c6c881bd6757a70f16",
"versionType": "git"
},
{
"status": "affected",
"version": "ec8a8f3c31ddef0a7d9626c4b8a4baa30f3b80aa",
"lessThan": "53d32735d77ab56cc3fc7bd53a7d099418f19be1",
"versionType": "git"
},
{
"status": "affected",
"version": "ec8a8f3c31ddef0a7d9626c4b8a4baa30f3b80aa",
"lessThan": "f0a83d0a4b7c127d32ac06d607a9214937716129",
"versionType": "git"
},
{
"status": "affected",
"version": "ec8a8f3c31ddef0a7d9626c4b8a4baa30f3b80aa",
"lessThan": "35f1943d242e1b9f0b6e91c0c93bfb293a9f8224",
"versionType": "git"
},
{
"status": "affected",
"version": "ec8a8f3c31ddef0a7d9626c4b8a4baa30f3b80aa",
"lessThan": "baed0d9ba91d4f390da12d5039128ee897253d60",
"versionType": "git"
}
],
"programFiles": [
"net/netfilter/nf_conntrack_h323_asn1.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "4.15"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "4.15",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "5.10.252",
"versionType": "semver",
"lessThanOrEqual": "5.10.*"
},
{
"status": "unaffected",
"version": "5.15.202",
"versionType": "semver",
"lessThanOrEqual": "5.15.*"
},
{
"status": "unaffected",
"version": "6.1.165",
"versionType": "semver",
"lessThanOrEqual": "6.1.*"
},
{
"status": "unaffected",
"version": "6.6.128",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.75",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.16",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "6.19.6",
"versionType": "semver",
"lessThanOrEqual": "6.19.*"
},
{
"status": "unaffected",
"version": "7.0",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"net/netfilter/nf_conntrack_h323_asn1.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-43233
Source reference:
/cveMetadata/cveId
Publisher severity
high
Source reference: /containers/cna/metrics
- Event
- #40048 · Revision 1
- Added to Heist Feed
- Publisher date