Live › vulnerability › CVE-2026-98549
Go to dashboardA flaw in the Linux kernel TCP retransmit queue can merge packets sent before and after a switch to device encryption, so some data is retransmitted in cleartext or the connection stalls. The sources do not state a confirmed attacker impact beyond these effects.
Summary written from the sources below. Check the originals before acting.
First seen by InfraStack 2026-10-23 21:57 UTC. All times on this page are UTC.
Systems running a Linux kernel with TCP device encryption (PSP) or TLS device offload enabled, where the affected collapse paths can run. The sources do not name the fixed kernel versions or confirm which configurations are reachable, so teams that do not use TLS device offload or PSP are likely unaffected, but the sources do not say so explicitly.
No product ranges from the sources yet.
Unknown from the sources.
Unknown from the sources.
Each row is the first time that source carried this signal. The analyst’s rows are its own findings.
In the Linux kernel, the following vulnerability has been resolved:
tcp: prevent collapsing skbs across boundary in rtx queue
tcp_write_collapse_fence() sets TCP_SKB_CB(skb)->eor = 1 on tcp_write_queue_tail(sk) to prevent skbs queued after a switch to device encryption from being collapsed into earlier skbs.
The fence is a no-op if all earlier data has already been transmitted when the switch happens: sk->sk_write_queue is empty. The not yet acknowledged earlier skbs wait in sk->tcp_rtx_queue with eor 0.
On a subsequent retransmit or SACK shift, tcp_retrans_try_collapse() or tcp_shift_skb_data() can then merge an skb queued after the switch into one queued before it.
Both users of the fence are affected:
psp: devices only encrypt skbs with skb->decrypted set. The merged skb keeps decrypted = 0 from the earlier skb, so merged data sent after psp_sock_assoc_set_tx() is retransmitted in cleartext.
tls device offload: the merged skb straddles the start marker set in tls_set_device_offload(). The software fallback (fill_sg_in() returns -EINVAL) and the mlx5, nfp and funeth drivers cannot handle such an skb and drop it. Every retransmit rebuilds the same skb, so the connection stalls.
Fix this in two places, for defense in depth:
Fall back to tcp_rtx_queue_tail(sk) in tcp_write_collapse_fence() when tcp_write_queue_tail(sk) is NULL.
Check !skb_cmp_decrypted(to, from) in tcp_skb_can_collapse(), as tcp_skb_can_collapse_rx() does on receive. skb_shift(), which both collapse paths call, already has a DEBUG_NET_WARN_ON_ONCE() for this condition.
This page as .md · .json · in your agent: get_signal("CVE-2026-98549")
NVD data is provided by NIST and is public domain. Posts quoted belong to their authors.