CVE-2025-39682
CISA 기관 조치 기한: 2026-09-21
Linux Kernel
Qualys 위협 인텔 · 심각도 4/5 · QID 163415 · OEL
공개 익스플로잇
측면이동
쉬운 악용
대량 데이터 유출
서비스 거부
원격코드실행
CISA KEV
In the Linux kernel, the following vulnerability has been resolved:
tls: fix handling of zero-length records on the rx_list
Each recvmsg() call must process either
- only contiguous DATA records (any number of them)
- one non-DATA record
If the next record has different type than what has already been
processed we break out of the main processing loop. If the record
has already been decrypted (which may be the case for TLS 1.3 where
we don't know type until decryption) we queue the pending record
to the rx_list. Next recvmsg() will pick it up from there.
Queuing the skb to rx_list after zero-copy decrypt is not possible,
since in that case we decrypted directly to the user space buffer,
and we don't have an skb to queue (darg.skb points to the ciphertext
skb for access to metadata like length).
Only data records are allowed zero-copy, and we break the processing
loop after each non-data record. So we should never zero-copy and
then find out that the record type has changed. The corner case
we missed is when the initial record comes from rx_list, and it's
zero length.
tls: fix handling of zero-length records on the rx_list
Each recvmsg() call must process either
- only contiguous DATA records (any number of them)
- one non-DATA record
If the next record has different type than what has already been
processed we break out of the main processing loop. If the record
has already been decrypted (which may be the case for TLS 1.3 where
we don't know type until decryption) we queue the pending record
to the rx_list. Next recvmsg() will pick it up from there.
Queuing the skb to rx_list after zero-copy decrypt is not possible,
since in that case we decrypted directly to the user space buffer,
and we don't have an skb to queue (darg.skb points to the ciphertext
skb for access to metadata like length).
Only data records are allowed zero-copy, and we break the processing
loop after each non-data record. So we should never zero-copy and
then find out that the record type has changed. The corner case
we missed is when the initial record comes from rx_list, and it's
zero length.
KEV 필수 조치: Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
타임라인
- NVD 공개
- CISA KEV 등재(실제 악용 확인) 공개 후 378일
- 첫 보도 The Hacker News · CISA, 실제 공격에 악용된 리눅스 커널 취약점 3건 경고
- 최근 보도 (총 4건) BleepingComputer · CISA, 3건의 리눅스 커널 취약점에 대한 공격이 활발히 진행 중…
- KISA 보안공지 Linux 커널 보안 업데이트 권고
- CISA 기관 조치 기한 경과
날짜 정보 없는 신호: 공개 PoC 2건
KISA 보호나라 보안공지
Linux 커널 보안 업데이트 권고
Linux 재단은 자사 제품에서 발생하는 취약점을 해결한 보안 업데이트 발표 [1]~[3] o 영향을 받는 버전을 사용 중인 사용자는 해결 방안에 따라 최신 버전으로 업데이트 권고
벡터: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
공개 익스플로잇 / PoC
- GitHub 공개 PoC 2건 — 대표 레포 ↗