Vulnerability in Linux

[ Description ]Official description

In the Linux kernel, the following vulnerability has been resolved: sunvdc: unmap LDC cookies when the descriptor send fails __send_request() maps the request's pages into the LDC channel's map table (ldc_map_sg()), fills in the descriptor and marks it VIO_DESC_READY before ringing the doorbell via __vdc_tx_trigger(). When the trigger fails, the error path only prints a message: the descriptor stays READY and the cookies are never unmapped. The mapping is normally released in vdc_end_one() when the peer completes the descriptor - but a descriptor whose doorbell was never sent will never complete, and since dr->prod is not advanced on failure, the reset path (vdc_requeue_inflight(), which walks [cons, prod)) never visits it either. The map table entries are leaked permanently. Since commit a11f6ca9aef9 ("sunvdc: Do not spin in an infinite loop when vio_ldc_send() returns EAGAIN") trigger failures occur in practice under load, so every resulting I/O error also leaks one request's worth of entries from the fixed-size (8192 entries per channel) map table. Because the allocator hands out contiguous ranges, fragmentation makes large multi-segment requests fail first as the table drains, until ldc_map_sg() fails permanently and the disk is dead until reboot. It also makes any retry-based recovery unusable: requeuing the request on -EAGAIN remaps the pages on every attempt, overwriting desc->cookies and orphaning the previous mapping, so the table drains at the retry rate. This is the memory exhaustion observed when the requeue approach was first tested in October 2025. Roll back on failure: unmap the cookies, mark the descriptor FREE again and clear the request entry. If the trigger failed with -ENOTCONN, __vdc_tx_trigger() has already reset the port, which tears down and reallocates both the dring and the LDC channel including its map table - nothing to roll back, and the stale descriptor must not be touched.

[ Fixes ]Fixes and patches

No fix or interim patch is linked from our sources yet. Check the vendor references below and limit exposure of affected systems until a fix is available.

[ Advisories ]Government CERT advisories

• CERT-FR9 Oct 2026CERTFR-2026-AVI-1289

  Multiple vulnerabilities in the Debian LTS Linux kernel Translated from French

  Multiple vulnerabilities have been discovered in the Debian LTS Linux kernel. Some of them allow an attacker to cause privilege escalation, a breach of data confidentiality and denial of service.

  CVE-2025-38237CVE-2025-39833CVE-2025-39925+1311 more CVEs
• CERT-FR2 Oct 2026CERTFR-2026-AVI-1253

  Multiple vulnerabilities in the Debian Linux kernel Translated from French

  Multiple vulnerabilities have been discovered in the Debian Linux kernel. Some of them allow an attacker to cause privilege escalation, a breach of data confidentiality and denial of service.

  CVE-2025-38237CVE-2025-39833CVE-2025-39925+1310 more CVEs
• BSI CERT-Bund24 Sep 2026WID-SEC-2026-3579

  Linux Kernel: Multiple vulnerabilities Translated from German

  CVE-2026-97615CVE-2026-97978CVE-2026-98127+590 more CVEs

[ References ]References

• git.kernel.org/stable/c/0c6da21fa35e03fc74f09895433ccd6d4a9c3530
• git.kernel.org/stable/c/24564576be423f3b5d7e67cd7df848ac66646497
• git.kernel.org/stable/c/57835952566f0be9b365a6eb3a70b397a9d5ef47
• git.kernel.org/stable/c/9251573e7cf7d797ae4a30b2a236af8242237a61
• git.kernel.org/stable/c/ab81a5c1014a38dab0fb402609fd866b0bcb4726
• git.kernel.org/stable/c/b0de6463667e9bb9dc14a83a9c24c1b6b3f7b5f7
• git.kernel.org/stable/c/eb9c5f6747fe98b83c78cb5476a914e91d50e8e8
• git.kernel.org/stable/c/f3322baa3a8ac87730feae952c1146269d78e098