lwt_bpf: Restore reserved headroom after xmit program
In the Linux kernel, the following vulnerability has been resolved: lwt_bpf: Restore reserved headroom after xmit program ip_finish_output2() expands an skb to LL_RESERVED_SPACE(dev) before LWT xmit. An LWT_XMIT BPF program can then modify the skb head and still return BPF_OK, so bpf_xmit() rechecks the remaining headroom before the skb continues to neighbour output. That recheck uses dst->dev->hard_header_len. This is not enough for the neighbour cached-header path: neigh_hh_output() copies the cached hardware header using the aligned hh_cache size, HH_DATA_MOD for short headers or HH_DATA_ALIGN(hh_len) otherwise. On Ethernet, hard_header_len is 14 but the cached copy needs 16 bytes. If an LWT_XMIT BPF program calls bpf_skb_change_head(skb, 1, 0), the skb can still have 15 bytes of headroom after the program. The existing check accepts that, after which neigh_hh_output() hits its headroom warning and drops the skb. Use LL_RESERVED_SPACE(dst->dev) in the post-BPF headroom check to match the reservation made before LWT xmit.
CVE-2026-90160
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-2026-90160
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": "3a0af8fd61f90920f6fa04e4f1e9a6a73c1b4fd2",
"lessThan": "753e5cdcca5474d230d62bb3489e5168ab27c272",
"versionType": "git"
},
{
"status": "affected",
"version": "3a0af8fd61f90920f6fa04e4f1e9a6a73c1b4fd2",
"lessThan": "c488071c3441fa34f5a87cd6c12ce2cc6304f20e",
"versionType": "git"
},
{
"status": "affected",
"version": "3a0af8fd61f90920f6fa04e4f1e9a6a73c1b4fd2",
"lessThan": "a38c0eb447e2dd0120a2ebcdba470f9505ac8907",
"versionType": "git"
},
{
"status": "affected",
"version": "3a0af8fd61f90920f6fa04e4f1e9a6a73c1b4fd2",
"lessThan": "de2b2004e16f2930eb689175e2c1998b0a68d499",
"versionType": "git"
},
{
"status": "affected",
"version": "3a0af8fd61f90920f6fa04e4f1e9a6a73c1b4fd2",
"lessThan": "7d043e24520a273c362be5dd7d9c82796879a49b",
"versionType": "git"
},
{
"status": "affected",
"version": "3a0af8fd61f90920f6fa04e4f1e9a6a73c1b4fd2",
"lessThan": "7cf561843ed0ad57501892a65abb77957e6c800f",
"versionType": "git"
},
{
"status": "affected",
"version": "3a0af8fd61f90920f6fa04e4f1e9a6a73c1b4fd2",
"lessThan": "179a5b2171573d94a25c9aa8e1c9f9ac352ad316",
"versionType": "git"
},
{
"status": "affected",
"version": "3a0af8fd61f90920f6fa04e4f1e9a6a73c1b4fd2",
"lessThan": "5fe7007aed9ad069b2bd77e5d0c875c64f5c0269",
"versionType": "git"
}
],
"programFiles": [
"net/core/lwt_bpf.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "4.10"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "4.10",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "5.10.270",
"versionType": "semver",
"lessThanOrEqual": "5.10.*"
},
{
"status": "unaffected",
"version": "5.15.221",
"versionType": "semver",
"lessThanOrEqual": "5.15.*"
},
{
"status": "unaffected",
"version": "6.1.188",
"versionType": "semver",
"lessThanOrEqual": "6.1.*"
},
{
"status": "unaffected",
"version": "6.6.157",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.110",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.52",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.2.6",
"versionType": "semver",
"lessThanOrEqual": "7.2.*"
},
{
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"net/core/lwt_bpf.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-90160
Source reference:
/cveMetadata/cveId
Publisher severity
No explicit severity was provided.
- Event
- #36548 · Revision 1
- Added to Heist Feed
- Publisher date