net/tcp-ao: fix use-after-free of current_key on reconnect to another peer
In the Linux kernel, the following vulnerability has been resolved: net/tcp-ao: fix use-after-free of current_key on reconnect to another peer tcp_inbound_ao_hash() is called before bh_lock_sock_nested() is taken, with only rcu_read_lock() held. On the fast path for established sockets, if the rnext_keyid sent by the peer differs from current_key->sndid, the key the peer asked for is looked up and stored in current_key. The lookup is inside the RCU read side, but current_key outlives it. When the socket is disconnected and connect() is called again for another peer, tcp_ao_connect_init() unlinks every key that does not match the new peer and frees it with call_rcu(). If current_key points at such a key, it is cleared to NULL. The fast path reads sk_state only once on entry, so a softirq that got into it while the socket was still established can update current_key after that loop has already run. The update is inside the RCU read side, so it comes before the call_rcu() callback, and once the callback frees the key, current_key is left pointing at freed memory. The next transmission picks that pointer up in tcp_get_current_key(). tcp_ao_transmit_skb() then reads the traffic key from the freed object, which is the use-after-free. Wait for one grace period before unlinking, and only if a key is going to be removed. By the time tcp_connect() runs the socket is already in TCP_SYN_SENT, and TCP_AO_ESTABLISHED does not contain TCPF_SYN_SENT, so a softirq entering after the wait cann
CVE-2026-80849
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-2026-80849
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": "0a3a809089eb1d4a0a2fd0c16b520d603988c859",
"lessThan": "84a93b4e012587d0a4a84ffb23ec6da18e9d85f9",
"versionType": "git"
},
{
"status": "affected",
"version": "0a3a809089eb1d4a0a2fd0c16b520d603988c859",
"lessThan": "73fde8fe4469f4ed8f0afcc0b9d6413002a9e6b3",
"versionType": "git"
},
{
"status": "affected",
"version": "0a3a809089eb1d4a0a2fd0c16b520d603988c859",
"lessThan": "e54ad693eddb40c595add013f545354c538e325b",
"versionType": "git"
},
{
"status": "affected",
"version": "0a3a809089eb1d4a0a2fd0c16b520d603988c859",
"lessThan": "2857dcbd03cf3354af0fba1b65c6a260fb43811a",
"versionType": "git"
},
{
"status": "affected",
"version": "0a3a809089eb1d4a0a2fd0c16b520d603988c859",
"lessThan": "da4471557f279d0f56605158a625bb6e49ef7d41",
"versionType": "git"
}
],
"programFiles": [
"net/ipv4/tcp_ao.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "6.7"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "6.7",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.12.108",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.49",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.1.13",
"versionType": "semver",
"lessThanOrEqual": "7.1.*"
},
{
"status": "unaffected",
"version": "7.2.3",
"versionType": "semver",
"lessThanOrEqual": "7.2.*"
},
{
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"net/ipv4/tcp_ao.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-80849
Source reference:
/cveMetadata/cveId
Publisher severity
No explicit severity was provided.
- Event
- #34864 · Revision 1
- Added to Heist Feed
- Publisher date