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CVE-2026-97952

Linux: sunvdc: unmap LDC cookies when the descriptor send fails

Linux LinuxOperating systems
Open in ThreatlineRecord JSON
CVSS
NoneNot scored
ExploitationNo known exploitationNot in CISA KEV, which does not prove it is unexploitedCISA KEV
Exploit odds (EPSS)0.18%Chance of exploitation activity in the next 30 days, higher than 6% of CVEs. Scored 23 Oct 2026FIRST EPSS
Fixed in24564576be423f3b5d7e67cd7df848ac66646497Also 9251573e7cf7d797ae4a30b2a236af8242237a61, 57835952566f0be9b365a6eb3a70b397a9d5ef47 and 6 moreCVE List
Published25 Sep 2026Updated 19 Oct 2026CVE List

What fixes it

  • 24564576be423f3b5d7e67cd7df848ac66646497LinuxCVE List
  • 9251573e7cf7d797ae4a30b2a236af8242237a61LinuxCVE List
  • 57835952566f0be9b365a6eb3a70b397a9d5ef47LinuxCVE List
  • 0c6da21fa35e03fc74f09895433ccd6d4a9c3530LinuxCVE List
  • 4.5LinuxCVE List
  • 4.10LinuxCVE List
Show all 9 fixed versions

A fixed version on one release line is not the upgrade target for every line. Check your exact version and any vendor backports.

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.

Text from CVE List

Affected versions 28

  • Linuxaffected: a11f6ca9aef989b56cd31ff4ee2af4fb31a172ec before eb9c5f6747fe98b83c78cb5476a914e91d50e8e8CVE List
  • Linuxaffected: a11f6ca9aef989b56cd31ff4ee2af4fb31a172ec before 24564576be423f3b5d7e67cd7df848ac66646497CVE List
  • Linuxaffected: a11f6ca9aef989b56cd31ff4ee2af4fb31a172ec before 9251573e7cf7d797ae4a30b2a236af8242237a61CVE List
  • Linuxaffected: a11f6ca9aef989b56cd31ff4ee2af4fb31a172ec before b0de6463667e9bb9dc14a83a9c24c1b6b3f7b5f7CVE List
  • Linuxaffected: a11f6ca9aef989b56cd31ff4ee2af4fb31a172ec before ab81a5c1014a38dab0fb402609fd866b0bcb4726CVE List
  • Linuxaffected: a11f6ca9aef989b56cd31ff4ee2af4fb31a172ec before 57835952566f0be9b365a6eb3a70b397a9d5ef47CVE List
  • Linuxaffected: a11f6ca9aef989b56cd31ff4ee2af4fb31a172ec before f3322baa3a8ac87730feae952c1146269d78e098CVE List
  • Linuxaffected: a11f6ca9aef989b56cd31ff4ee2af4fb31a172ec before 0c6da21fa35e03fc74f09895433ccd6d4a9c3530CVE List
  • Linuxaffected: 627e656239c63d8a81672d08de7885e89c12fa75CVE List
  • Linuxaffected: a1ef7d5da9b2c145f811a80bb8197df6037a7572CVE List
  • Linuxaffected: 7ab4b6526fdcdfa7772984bbcd2ac4fd14fa223bCVE List
  • Linuxaffected: 3fbba4e55051d01a72b56ea192064175924bf56aCVE List
  • Linuxaffected: 3e380fc2ae4d18210eec9c472b12e2b2544f7dc1CVE List
  • Linuxaffected: 4.4.175 before 4.5CVE List
  • Linuxaffected: 4.9.156 before 4.10CVE List
  • Linuxaffected: 4.14.99 before 4.15CVE List
  • Linuxaffected: 4.19.21 before 4.20CVE List
  • Linuxaffected: 4.20.8 before 4.21CVE List
  • Linuxaffected: 5.0CVE List
  • Linuxunaffected: all versions before 5.0CVE List
  • Linuxunaffected: 5.10.271 through 5.10.*CVE List
  • Linuxunaffected: 5.15.222 through 5.15.*CVE List
  • Linuxunaffected: 6.1.189 through 6.1.*CVE List
  • Linuxunaffected: 6.6.158 through 6.6.*CVE List
  • Linuxunaffected: 6.12.111 through 6.12.*CVE List
  • Linuxunaffected: 6.18.53 through 6.18.*CVE List
  • Linuxunaffected: 7.2.7 through 7.2.*CVE List
  • Linuxunaffected: 7.3CVE List

References 8