CVE-2026-98925
Received
Received - Intake
Double-Counting TCP Sequence in Linux Kernel
Vulnerability report for CVE-2026-98925, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.
Publication date: 2026-10-23
Last updated on: 2026-10-23
Assigner: kernel.org
Description
Description
In the Linux kernel, the following vulnerability has been resolved:
bpf, sockmap: Fix self-redirect copied_seq double-counting
When a BPF stream_verdict program redirects an skb back to the same
socket (self-redirect with BPF_F_INGRESS), sk_psock_verdict_apply()
calls tcp_eat_skb() which advances tcp_sk->copied_seq. However, the
skb is then delivered to the socket's psock ingress queue and later
read by tcp_bpf_recvmsg_parser(), which also advances copied_seq via
the copied_from_self accounting path. This double-counting causes
copied_seq to advance by 2x the actual data length, triggering:
TCP recvmsg seq # bug 2: copied BF2E806, seq BF2E7FD, \
rcvnxt BF2E806, fl 0
WARNING: net/ipv4/tcp.c:2745 at tcp_recvmsg_locked+0x72b/0x2640
Call Trace:
tcp_recvmsg+0x10a/0x500
sock_recvmsg+0x168/0x1d0
__sys_recvfrom+0x19a/0x2a0
__x64_sys_recvfrom+0xe4/0x1f0
do_syscall_64+0xf7/0x530
entry_SYSCALL_64_after_hwframe+0x77/0x7f
cleanup rbuf bug: copied BF2E806 seq BF2E806 rcvnxt BF2E806
WARNING: net/ipv4/tcp.c:1609 at tcp_cleanup_rbuf+0xf2/0x1c0
Call Trace:
tcp_recvmsg_locked+0x8d1/0x2640
tcp_recvmsg+0x10a/0x500
sock_recvmsg+0x168/0x1d0
__sys_recvfrom+0x19a/0x2a0
__x64_sys_recvfrom+0xe4/0x1f0
do_syscall_64+0xf7/0x530
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Fix this by converting self-redirect verdict to __SK_PASS at the
beginning of sk_psock_verdict_apply(). This bypasses the
__SK_REDIRECT case entirely (which calls sk_psock_eat_skb), letting
the __SK_PASS path queue the skb to the psock ingress queue. The
data is then read via tcp_bpf_recvmsg_parser(), which advances
copied_seq exactly once through copied_from_self. Cross-socket
redirects continue through __SK_REDIRECT with sk_psock_eat_skb()
unchanged.
CVSS Scores
EPSS Scores
| Probability: | |
| Percentile: |
Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| Linux | Linux | fe735073a50eaa71aceb2e990827fe26f33cddd6 |
| Linux | Linux | e5c6de5fa025882babf89cecbed80acf49b987fa |
| Linux | Linux | e5c6de5fa025882babf89cecbed80acf49b987fa |
| Linux | Linux | e5c6de5fa025882babf89cecbed80acf49b987fa |
| Linux | Linux | e5c6de5fa025882babf89cecbed80acf49b987fa |
| Linux | Linux | e5c6de5fa025882babf89cecbed80acf49b987fa |
| Linux | Linux | f9b4a0b537be7a6e5f002ca64b09dcca9c14e6ed |
| Linux | Linux | 6.1.32 |
| Linux | Linux | 6.3.6 |
| Linux | Linux | 6.4 |
Helpful Resources
Exploitability
CWE
KEV
| CWE ID | Description |
|---|---|
| CWE-UNKNOWN |
