Summary
In the Linux kernel, the following vulnerability has been resolved: tcpbpf: Call skmsg_free()...
In the Linux kernel, the following vulnerability has been resolved:
tcp_bpf: Call sk_msg_free() when tcp_bpf_send_verdict() fails to allocate psock->cork.
syzbot reported the splat below. [0]
The repro does the following:
- Load a sk_msg prog that calls bpf_msg_cork_bytes(msg, cork_bytes)
- Attach the prog to a SOCKMAP
- Add a socket to the SOCKMAP
- Activate fault injection
- Send data less than cork_bytes
At 5., the data is carried over to the next sendmsg() as it is
smaller than the cork_bytes specified by bpf_msg_cork_bytes().
Then, tcp_bpf_send_verdict() tries to allocate psock->cork to hold
the data, but this fails silently due to fault injection + __GFP_NOWARN.
If the allocation fails, we need to revert the sk->sk_forward_alloc
change done by sk_msg_alloc().
Let's call sk_msg_free() when tcp_bpf_send_verdict fails to allocate
psock->cork.
The "*copied" also needs to be updated such that a proper error can
be returned to the caller, sendmsg. It fails to allocate psock->cork.
Nothing has been corked so far, so this patch simply sets "*copied"
to 0.
[0]:
WARNING: net/ipv4/af_inet.c:156 at inet_sock_destruct+0x623/0x730 net/ipv4/af_inet.c:156, CPU#1: syz-executor/5983
Modules linked in:
CPU: 1 UID: 0 PID: 5983 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:inet_sock_destruct+0x623/0x730 net/ipv4/af_inet.c:156
Code: 0f 0b 90 e9 62 fe ff ff e8 7a db b5 f7 90 0f 0b 90 e9 95 fe ff ff e8 6c db b5 f7 90 0f 0b 90 e9 bb fe ff ff e8 5e db b5 f7 90 <0f> 0b 90 e9 e1 fe ff ff 89 f9 80 e1 07 80 c1 03 38 c1 0f 8c 9f fc
RSP: 0018:ffffc90000a08b48 EFLAGS: 00010246
RAX: ffffffff8a09d0b2 RBX: dffffc0000000000 RCX: ffff888024a23c80
RDX: 0000000000000100 RSI: 0000000000000fff RDI: 0000000000000000
RBP: 0000000000000fff R08: ffff88807e07c627 R09: 1ffff1100fc0f8c4
R10: dffffc0000000000 R11: ffffed100fc0f8c5 R12: ffff88807e07c380
R13: dffffc0000000000 R14: ffff88807e07c60c R15: 1ffff1100fc0f872
FS: 00005555604c4500(0000) GS:ffff888125af1000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005555604df5c8 CR3: 0000000032b06000 CR4: 00000000003526f0
Call Trace:
__sk_destruct+0x86/0x660 net/core/sock.c:2339
rcu_do_batch kernel/rcu/tree.c:2605 [inline]
rcu_core+0xca8/0x1770 kernel/rcu/tree.c:2861
handle_softirqs+0x286/0x870 kernel/softirq.c:579
__do_softirq kernel/softirq.c:613 [inline]
invoke_softirq kernel/softirq.c:453 [inline]
__irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:680
irq_exit_rcu+0x9/0x30 kernel/softirq.c:696
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline]
sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1052
Impact
CVE-2025-39913 has a CVSS score of 7.8 (High). The vector is requires local access, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. No fixed version is listed yet, so configuration controls and monitoring matter more in the interim.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Frequently Asked Questions
- What is CVE-2025-39913? CVE-2025-39913 is a high-severity security vulnerability. No fixed version is listed yet.
- How severe is CVE-2025-39913? CVE-2025-39913 has a CVSS score of 7.8 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Is there a fix for CVE-2025-39913? No fixed version is listed for CVE-2025-39913 yet. Monitor the advisory for updates and apply mitigations in the interim.
- Is CVE-2025-39913 exploitable, and should I be worried? Whether CVE-2025-39913 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2025-39913 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.