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.
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.
Published:
2026-10-23
Score:
n/a
EPSS:
n/a
KEV:
No
Analysis
Analysis and contextual insights are available on OpenCVE Cloud.
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||||||||||||||||||||||||||
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| Linux | Linux | unaffected |
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| Linux | Linux | affected |
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Remediation
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References
History
Fri, 23 Oct 2026 12:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| 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. | |
| Title | bpf, sockmap: Fix self-redirect copied_seq double-counting | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
|
MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-10-23T12:05:53.207Z
Reserved: 2026-09-25T10:25:14.380Z
Link: CVE-2026-98925
Vulnrichment
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NVD
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Redhat
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OpenCVE Enrichment
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Weaknesses
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