AZL-102935
See a problem?- Import Source
- https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-102935.json
- JSON Data
- https://api.osv.dev/v1/vulns/AZL-102935
- Upstream
- Published
- 2026-09-17T17:17:09Z
- Modified
- 2026-09-18T14:18:02Z
- Summary
- CVE-2026-90160 affecting package kernel 6.6.150.1-1
- Details
-
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.
- References