DEBIAN-CVE-2025-40186

In the Linux kernel, the following vulnerability has been resolved: tcp: Don't call reqskfastopenremove() in tcpconnrequest(). syzbot reported the splat below in tcpconnrequest(). [0] If a listener is close()d while a TFO socket is being processed in tcpconnrequest(), inetcskreqskqueueadd() does not set reqsk->sk and calls inetchildforget(), which calls tcpdisconnect() for the TFO socket. After the cited commit, tcpdisconnect() calls reqskfastopenremove(), where reqskput() is called due to !reqsk->sk. Then, reqskfastopenremove() in tcpconnrequest() decrements the last req->rskrefcnt and frees reqsk, and _reqskfree() at the dropandfree label causes the refcount underflow for the listener and double-free of the reqsk. Let's remove reqskfastopenremove() in tcpconnrequest(). Note that other callers make sure tp->fastopenrsk is not NULL. [0]: refcountt: underflow; use-after-free. WARNING: CPU: 12 PID: 5563 at lib/refcount.c:28 refcountwarnsaturate (lib/refcount.c:28) Modules linked in: CPU: 12 UID: 0 PID: 5563 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 RIP: 0010:refcountwarnsaturate (lib/refcount.c:28) Code: ab e8 8e b4 98 ff 0f 0b c3 cc cc cc cc cc 80 3d a4 e4 d6 01 00 75 9c c6 05 9b e4 d6 01 01 48 c7 c7 e8 df fb ab e8 6a b4 98 ff <0f> 0b e9 03 5b 76 00 cc 80 3d 7d e4 d6 01 00 0f 85 74 ff ff ff c6 RSP: 0018:ffffa79fc0304a98 EFLAGS: 00010246 RAX: d83af4db1c6b3900 RBX: ffff9f65c7a69020 RCX: d83af4db1c6b3900 RDX: 0000000000000000 RSI: 00000000ffff7fff RDI: ffffffffac78a280 RBP: 000000009d781b60 R08: 0000000000007fff R09: ffffffffac6ca280 R10: 0000000000017ffd R11: 0000000000000004 R12: ffff9f65c7b4f100 R13: ffff9f65c7d23c00 R14: ffff9f65c7d26000 R15: ffff9f65c7a64ef8 FS: 00007f9f962176c0(0000) GS:ffff9f65fcf00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000000180 CR3: 000000000dbbe006 CR4: 0000000000372ef0 Call Trace: <IRQ> tcpconnrequest (./include/linux/refcount.h:400 ./include/linux/refcount.h:432 ./include/linux/refcount.h:450 ./include/net/sock.h:1965 ./include/net/requestsock.h:131 net/ipv4/tcpinput.c:7301) tcprcvstateprocess (net/ipv4/tcpinput.c:6708) tcpv6dorcv (net/ipv6/tcpipv6.c:1670) tcpv6rcv (net/ipv6/tcpipv6.c:1906) ip6protocoldeliverrcu (net/ipv6/ip6input.c:438) ip6input (net/ipv6/ip6input.c:500) ipv6rcv (net/ipv6/ip6input.c:311) _netifreceiveskb (net/core/dev.c:6104) processbacklog (net/core/dev.c:6456) _napipoll (net/core/dev.c:7506) netrxaction (net/core/dev.c:7569 net/core/dev.c:7696) handlesoftirqs (kernel/softirq.c:579) do_softirq (kernel/softirq.c:480) </IRQ>

References

https://security-tracker.debian.org/tracker/CVE-2025-40186

Affected packages

Debian:11 / linux

Package

Name: linux
Purl: pkg:deb/debian/linux?arch=source

Affected ranges

Type: ECOSYSTEM
Events: Introduced

0Unknown introduced version / All previous versions are affected

Fixed

5.10.247-1

Affected versions

5.*

5.10.46-4

5.10.46-5

5.10.70-1~bpo10+1

5.10.70-1

5.10.84-1

5.10.92-1~bpo10+1

5.10.92-1

5.10.92-2

5.10.103-1~bpo10+1

5.10.103-1

5.10.106-1

5.10.113-1

5.10.120-1~bpo10+1

5.10.120-1

5.10.127-1

5.10.127-2~bpo10+1

5.10.127-2

5.10.136-1

5.10.140-1

5.10.148-1

5.10.149-1

5.10.149-2

5.10.158-1

5.10.158-2

5.10.162-1

5.10.178-1

5.10.178-2

5.10.178-3

5.10.179-1

5.10.179-2

5.10.179-3

5.10.179-4

5.10.179-5

5.10.191-1

5.10.197-1

5.10.205-1

5.10.205-2

5.10.209-1

5.10.209-2

5.10.216-1

5.10.218-1

5.10.221-1

5.10.223-1

5.10.226-1

5.10.234-1

5.10.237-1

5.10.244-1

Ecosystem specific

{
    "urgency": "not yet assigned"
}

Debian:12 / linux

Package

Name: linux
Purl: pkg:deb/debian/linux?arch=source

Affected ranges

Type: ECOSYSTEM
Events: Introduced

0Unknown introduced version / All previous versions are affected

Fixed

6.1.158-1

Affected versions

6.*

6.1.27-1

6.1.37-1

6.1.38-1

6.1.38-2~bpo11+1

6.1.38-2

6.1.38-3

6.1.38-4~bpo11+1

6.1.38-4

6.1.52-1

6.1.55-1~bpo11+1

6.1.55-1

6.1.64-1

6.1.66-1

6.1.67-1

6.1.69-1~bpo11+1

6.1.69-1

6.1.76-1~bpo11+1

6.1.76-1

6.1.82-1

6.1.85-1

6.1.90-1~bpo11+1

6.1.90-1

6.1.94-1~bpo11+1

6.1.94-1

6.1.98-1

6.1.99-1

6.1.106-1

6.1.106-2

6.1.106-3

6.1.112-1

6.1.115-1

6.1.119-1

6.1.123-1

6.1.124-1

6.1.128-1

6.1.129-1

6.1.133-1

6.1.135-1

6.1.137-1

6.1.139-1

6.1.140-1

6.1.147-1

6.1.148-1

6.1.153-1

Ecosystem specific

{
    "urgency": "not yet assigned"
}

Debian:13 / linux

Package

Name: linux
Purl: pkg:deb/debian/linux?arch=source

Affected ranges

Type: ECOSYSTEM
Events: Introduced

0Unknown introduced version / All previous versions are affected

Fixed

6.12.57-1

Affected versions

6.*

6.12.38-1

6.12.41-1

6.12.43-1~bpo12+1

6.12.43-1

6.12.48-1

6.12.57-1~bpo12+1

Ecosystem specific

{
    "urgency": "not yet assigned"
}

Debian:14 / linux

Package

Name: linux
Purl: pkg:deb/debian/linux?arch=source

Affected ranges

Type: ECOSYSTEM
Events: Introduced

0Unknown introduced version / All previous versions are affected

Fixed

6.17.6-1

Affected versions

6.*

6.12.38-1

6.12.41-1

6.12.43-1~bpo12+1

6.12.43-1

6.12.48-1

6.12.57-1~bpo12+1

6.12.57-1

6.13~rc6-1~exp1

6.13~rc7-1~exp1

6.13.2-1~exp1

6.13.3-1~exp1

6.13.4-1~exp1

6.13.5-1~exp1

6.13.6-1~exp1

6.13.7-1~exp1

6.13.8-1~exp1

6.13.9-1~exp1

6.13.10-1~exp1

6.13.11-1~exp1

6.14.3-1~exp1

6.14.5-1~exp1

6.14.6-1~exp1

6.15~rc7-1~exp1

6.15-1~exp1

6.15.1-1~exp1

6.15.2-1~exp1

6.15.3-1~exp1

6.15.4-1~exp1

6.15.5-1~exp1

6.15.6-1~exp1

6.16~rc7-1~exp1

6.16-1~exp1

6.16.1-1~exp1

6.16.3-1~bpo13+1

6.16.3-1

6.16.5-1

6.16.6-1

6.16.7-1

6.16.8-1

6.16.9-1

6.16.10-1

6.16.11-1

6.16.12-1~bpo13+1

6.16.12-1

6.16.12-2

6.17.2-1~exp1

6.17.5-1~exp1

Ecosystem specific

{
    "urgency": "not yet assigned"
}

Debian:11 / linux-6.1

Package

Name: linux-6.1
Purl: pkg:deb/debian/linux-6.1?arch=source

Affected ranges

Type: ECOSYSTEM
Events: Introduced

0Unknown introduced version / All previous versions are affected

Fixed

6.1.158-1~deb11u1

Affected versions

6.*

6.1.106-3~deb11u1

6.1.106-3~deb11u2

6.1.106-3~deb11u3

6.1.112-1~deb11u1

6.1.119-1~deb11u1

6.1.128-1~deb11u1

6.1.129-1~deb11u1

6.1.137-1~deb11u1

6.1.140-1~deb11u1

6.1.147-1~deb11u1

6.1.148-1~deb11u1

6.1.153-1~deb11u1

Ecosystem specific

{
    "urgency": "not yet assigned"
}