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VulnerabilityPublished Updated

CVE-2026-68159: Linux kernel · libceph: bound pg_{temp,upmap,upmap_items} length to CEPH_PG_MAX_SIZE

Affects Linux kernelSource CVE Database V5

0

Not known to be exploited · CVSS 9.8 Critical · fixed in ebdf4b4f3b1474079980a2e5cd79ad65fb54db57 : patch Linux kernel as a priority.

Data as of 26 Oct 2026, 13:07 UTC

CVSS 3.1 base score
9.8Critical
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.7% chance of exploitation in 30 days – higher than 54% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CISA SSVC
Exploitation
No evidence of active exploitation and no public proof of concept
Automatable
Attackers can reliably automate steps 1–4 of the kill chain
Technical impact
Total control over the software or total information disclosure

CISA SSVC assessment, 2026-10-16.

Patch
Available – fixed in ebdf4b4f3b1474079980a2e5cd79ad65fb54db57, e36663145abd7024f0281dfb22fdef65f185845b, d5650ddbd4d42c1a916c8fe1a4c4cb573ef810a1 +5
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 10 Aug 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • ≥ a303bb0e58345fe9f7ab2f82b90266f2b5036058, < ebdf4b4f3b1474079980a2e5cd79ad65fb54db57
Fixed in
  • ebdf4b4f3b1474079980a2e5cd79ad65fb54db57
LinuxLinuxAffected
  • ≥ a303bb0e58345fe9f7ab2f82b90266f2b5036058, < e36663145abd7024f0281dfb22fdef65f185845b
Fixed in
  • e36663145abd7024f0281dfb22fdef65f185845b
LinuxLinuxAffected
  • ≥ a303bb0e58345fe9f7ab2f82b90266f2b5036058, < d5650ddbd4d42c1a916c8fe1a4c4cb573ef810a1
Fixed in
  • d5650ddbd4d42c1a916c8fe1a4c4cb573ef810a1
LinuxLinuxAffected
  • ≥ a303bb0e58345fe9f7ab2f82b90266f2b5036058, < 590b07ceea138d49c9b64f65d263aa902d3b4730
Fixed in
  • 590b07ceea138d49c9b64f65d263aa902d3b4730
LinuxLinuxAffected
  • ≥ a303bb0e58345fe9f7ab2f82b90266f2b5036058, < 66eec4af1e080b695229c9a20635648a6d12fedf
Fixed in
  • 66eec4af1e080b695229c9a20635648a6d12fedf
LinuxLinuxAffected
  • ≥ a303bb0e58345fe9f7ab2f82b90266f2b5036058, < 42bc06c67d94d5f2a6b33294b0c4b07d8a47c515
Fixed in
  • 42bc06c67d94d5f2a6b33294b0c4b07d8a47c515

Description

In the Linux kernel, the following vulnerability has been resolved: libceph: bound pg_{temp,upmap,upmap_items} length to CEPH_PG_MAX_SIZE __decode_pg_temp() decodes an user-controlled length but only rejects values large enough to overflow the allocation; it does not bound it to CEPH_PG_MAX_SIZE. The helper backs both pg_temp and pg_upmap decoding, and apply_upmap()/get_temp_osds() later copy the decoded list into the fixed-size on-stack array struct ceph_osds.osds[CEPH_PG_MAX_SIZE]. A monitor that sends an OSDMap with a pg_temp/pg_upmap entry longer than 32 thus causes a stack out-of-bounds write. An OSD set for a single PG can never exceed CEPH_PG_MAX_SIZE, so reject longer entries at decode time. The bound is well below the old overflow threshold, so it also covers the allocation-size overflow the previous check guarded against. BUG: KASAN: stack-out-of-bounds in ceph_pg_to_up_acting_osds Write of size 4 ... by task exploit kasan_report (mm/kasan/report.c:595) ceph_pg_to_up_acting_osds (net/ceph/osdmap.c:2617 net/ceph/osdmap.c:2833) calc_target (net/ceph/osd_client.c:1638) __submit_request (net/ceph/osd_client.c:2394) ceph_osdc_start_request (net/ceph/osd_client.c:2490) ceph_osdc_call (net/ceph/osd_client.c:5164) rbd_dev_image_probe (drivers/block/rbd.c:6899) do_rbd_add (drivers/block/rbd.c:7138) ... kernel BUG at net/ceph/osdmap.c:2670! [ idryomov: do the same in __decode_pg_upmap_items() ]

References

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