CVE-2026-98287 pppoatm: ensure a writable skb header and linear data
A local attacker can trigger memory corruption in the Linux kernel PPPoATM driver via bridged packets, potentially leading to code execution or privilege escalation.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-98287?
CVE-2026-98287 is a memory corruption vulnerability in Linux, published on 6 Oct 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
pppoatm: ensure a writable skb header and linear data
In pppoatm_send(), LLC encapsulation checks whether there is sufficient headroom for the 4-byte LLC header, but does not ensure that the skb header is writable.
Normal transmit packets passing through ppp_start_xmit() have their header unshared via skb_cow_head(). However, packets can also reach pppoatm_send() via PPP channel bridging (PPPIOCBRIDGECHAN) without going through ppp_start_xmit().
Use skb_cow_head() to ensure both sufficient headroom and a writable header before pushing the LLC header.
While at it: - Call pskb_may_pull(skb, 1) before inspecting skb->data[0] to prevent out-of-bounds reads on zero-length or non-linear frames (e.g. from bridging). - Defer SC_COMP_PROT protocol compression until after pppoatm_may_send() succeeds. This eliminates the temporary skb allocation on admission failure and completely removes the fragile "undo" heuristic at the nospace label, avoiding any risk of reading uninitialized headroom or performing an unbalanced skb_push().
Which versions are affected by CVE-2026-98287?
How do I fix CVE-2026-98287?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-98287 being exploited?
There is no known exploitation of CVE-2026-98287 in the wild and no public exploit code.
Sources
Also known as AZL-106313, BELL-CVE-2026-98287, DEBIAN-CVE-2026-98287, GHSA-m2p4-c77r-p2c7, UBUNTU-CVE-2026-98287.