ppp_synctty: ensure a writeable skb header
In the Linux kernel, the following vulnerability has been resolved: ppp_synctty: ensure a writeable skb header ppp_sync_txmunge() checks headroom before prepending the address and control bytes, but does not ensure that the skb header is writable. A received skb can reach this function through PPP channel bridging without passing through ppp_start_xmit(), which calls skb_cow_head(). For example, a PPPoE frame may share its buffer with a clone queued to an AF_PACKET socket. If it is bridged to a synchronous tty channel, the address/control bytes can overwrite data still visible to that socket. Use skb_cow_head() to ensure both sufficient headroom and a writable header.
CVE-2026-97964
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-2026-97964
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": "4cf476ced45d7f12df30a68e833b263e7a2202d1",
"lessThan": "25e03eeead2c49748c7582dfb64c205f93a42d00",
"versionType": "git"
},
{
"status": "affected",
"version": "4cf476ced45d7f12df30a68e833b263e7a2202d1",
"lessThan": "a256f9925288ef47de8febed5c38d5cc21340211",
"versionType": "git"
},
{
"status": "affected",
"version": "4cf476ced45d7f12df30a68e833b263e7a2202d1",
"lessThan": "7953946f68262a8bb137aa101249adef6e029652",
"versionType": "git"
},
{
"status": "affected",
"version": "4cf476ced45d7f12df30a68e833b263e7a2202d1",
"lessThan": "3af7797fbabc84992e0ca5ad2bc0ca8537d053ef",
"versionType": "git"
},
{
"status": "affected",
"version": "4cf476ced45d7f12df30a68e833b263e7a2202d1",
"lessThan": "0996c3e6bcc6ae08cb371ed43648c9f7f748ae6e",
"versionType": "git"
},
{
"status": "affected",
"version": "4cf476ced45d7f12df30a68e833b263e7a2202d1",
"lessThan": "15d0a6c9a42df2d745c37510dba828f6dbe60d9f",
"versionType": "git"
},
{
"status": "affected",
"version": "4cf476ced45d7f12df30a68e833b263e7a2202d1",
"lessThan": "8aaeb56aff2a557a88f83ae866da2c91ad247e59",
"versionType": "git"
}
],
"programFiles": [
"drivers/net/ppp/ppp_synctty.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "5.11"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "5.11",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "5.15.222",
"versionType": "semver",
"lessThanOrEqual": "5.15.*"
},
{
"status": "unaffected",
"version": "6.1.189",
"versionType": "semver",
"lessThanOrEqual": "6.1.*"
},
{
"status": "unaffected",
"version": "6.6.158",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.111",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.53",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.2.7",
"versionType": "semver",
"lessThanOrEqual": "7.2.*"
},
{
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"drivers/net/ppp/ppp_synctty.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-97964
Source reference:
/cveMetadata/cveId
Publisher severity
No explicit severity was provided.
- Event
- #38100 · Revision 1
- Added to Heist Feed
- Publisher date