CVE-2025-38723

  • Published: 2025-09-04T16:15:42.130

In the Linux kernel, the following vulnerability has been resolved:

LoongArch: BPF: Fix jump offset calculation in tailcall

The extra pass of bpf_int_jit_compile() skips JIT context initialization
which essentially skips offset calculation leaving out_offset = -1, so
the jmp_offset in emit_bpf_tail_call is calculated by

“#define jmp_offset (out_offset – (cur_offset))”

is a negative number, which is wrong. The final generated assembly are
as follow.

54: bgeu $a2, $t1, -8 # 0x0000004c
58: addi.d $a6, $s5, -1
5c: bltz $a6, -16 # 0x0000004c
60: alsl.d $t2, $a2, $a1, 0x3
64: ld.d $t2, $t2, 264
68: beq $t2, $zero, -28 # 0x0000004c

Before apply this patch, the follow test case will reveal soft lock issues.

cd tools/testing/selftests/bpf/
./test_progs –allow=tailcalls/tailcall_bpf2bpf_1

dmesg:
watchdog: BUG: soft lockup – CPU#2 stuck for 26s! [test_progs:25056]

Related CVE by CWE

No related CWE found.

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How to fix CVE-2025-38723

CVE-2025-38723 is a unknown severity vulnerability affecting the affected product.

Description: In the Linux kernel, the following vulnerability has been resolved: LoongArch: BPF: Fix jump offset calculation in tailcall The extra pass of bpf_int_jit_compile() skips JIT context initialization which essentially skips offset calculation leaving out_offset = -1, so the jmp_offset in emit_bpf_tail_call is calculated by “#define jmp_offset (out_offset – (cur_offset))” is a negative number, which is […]

Exploit Difficulty: HARD
⏱️ Time to exploit: > 4 hours
🛠️ Required skills: Advanced security expertise
💰 Public exploits: Rare or not public

How to Fix:

1 Identify affected systems

- Check if you're running the affected product

2 Immediate actions

- Update to the latest patched version
- If patching is not immediately possible: restrict network exposure, apply least-privilege access

3 Verification

- Test the fix in a staging environment first
- Review logs for signs of exploitation
- Monitor for IOCs (Indicators of Compromise)

4 Long-term prevention

- Enable automatic security updates
- Set up vulnerability monitoring
- Review and harden security configurations

Exploit Difficulty Assessment

HARD
⏱️ Time to Exploit: > 4 hours
🛠️ Skills Required: Advanced security expertise
💰 Public Exploits: Rare or not public

Vulnerability Timeline

Sep 04, 2025
Vulnerability Published

CVE details first published to NVD database

Nov 12, 2025
Imported to Database

Added to this CVE tracking system

Detection Rules & IOCs

No specific detection rules generated for this vulnerability type.

No vendor/product data available.