netfilter: nf_conntrack_sip: fix use of uninitialized rtp_addr in process_sdp
In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_conntrack_sip: fix use of uninitialized rtp_addr in process_sdp process_sdp() declares union nf_inet_addr rtp_addr on the stack and passes it to the nf_nat_sip sdp_session hook after walking the SDP media descriptions. However rtp_addr is only initialized inside the media loop when a recognized media type with a non-zero port is found. If the SDP body contains no m= lines, only inactive media sections (m=audio 0 ...) or only unrecognized media types, rtp_addr is never assigned. Despite that, the function still calls hooks->sdp_session() with &rtp_addr, causing nf_nat_sdp_session() to format the stale stack value as an IP address and rewrite the SDP session owner and connection lines with it. With CONFIG_INIT_STACK_ALL_ZERO (default on most distributions) this results in the session-level o= and c= addresses being rewritten to 0.0.0.0 for inactive SDP sessions. Without stack auto-init the rewritten address is whatever happened to be on the stack. Fix this by pre-initializing rtp_addr from the session-level connection address (caddr) when available, and tracking via a have_rtp_addr flag whether any valid address was established. Skip the sdp_session hook entirely when no valid address exists.
CVE-2026-31427
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-2026-31427
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": "4ab9e64e5e3c0516577818804aaf13a630d67bc9",
"lessThan": "faa6ea32797a1847790514ff0da1be1d09771580",
"versionType": "git"
},
{
"status": "affected",
"version": "4ab9e64e5e3c0516577818804aaf13a630d67bc9",
"lessThan": "82baeb871e8f04906bc886273fdf0209e1754eb3",
"versionType": "git"
},
{
"status": "affected",
"version": "4ab9e64e5e3c0516577818804aaf13a630d67bc9",
"lessThan": "6e5e3c87b7e6212f1d8414fc2e4d158b01e12025",
"versionType": "git"
},
{
"status": "affected",
"version": "4ab9e64e5e3c0516577818804aaf13a630d67bc9",
"lessThan": "fe463e76c9b4b0b43b5ee8961b4c500231f1a3f6",
"versionType": "git"
},
{
"status": "affected",
"version": "4ab9e64e5e3c0516577818804aaf13a630d67bc9",
"lessThan": "7edca70751b9bdb5b83eed53cde21eccf3c86147",
"versionType": "git"
},
{
"status": "affected",
"version": "4ab9e64e5e3c0516577818804aaf13a630d67bc9",
"lessThan": "01f34a80ac23ae90b1909b94b4ed05343a62f646",
"versionType": "git"
},
{
"status": "affected",
"version": "4ab9e64e5e3c0516577818804aaf13a630d67bc9",
"lessThan": "52fdda318ef2362fc5936385bcb8b3d0328ee629",
"versionType": "git"
},
{
"status": "affected",
"version": "4ab9e64e5e3c0516577818804aaf13a630d67bc9",
"lessThan": "6a2b724460cb67caed500c508c2ae5cf012e4db4",
"versionType": "git"
}
],
"programFiles": [
"net/netfilter/nf_conntrack_sip.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "2.6.26"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "2.6.26",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "5.10.253",
"versionType": "semver",
"lessThanOrEqual": "5.10.*"
},
{
"status": "unaffected",
"version": "5.15.203",
"versionType": "semver",
"lessThanOrEqual": "5.15.*"
},
{
"status": "unaffected",
"version": "6.1.168",
"versionType": "semver",
"lessThanOrEqual": "6.1.*"
},
{
"status": "unaffected",
"version": "6.6.131",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.80",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.21",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "6.19.11",
"versionType": "semver",
"lessThanOrEqual": "6.19.*"
},
{
"status": "unaffected",
"version": "7.0",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"net/netfilter/nf_conntrack_sip.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-31427
Source reference:
/cveMetadata/cveId
Publisher severity
No explicit severity was provided.
- Event
- #28275 · Revision 1
- Added to Heist Feed
- Publisher date