{"resultsPerPage":1,"startIndex":0,"totalResults":1,"format":"NVD_CVE","version":"2.0","timestamp":"2026-04-15T06:38:50.352","vulnerabilities":[{"cve":{"id":"CVE-2025-39879","sourceIdentifier":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","published":"2025-09-23T06:15:47.523","lastModified":"2026-01-14T20:16:10.457","vulnStatus":"Modified","cveTags":[],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nceph: always call ceph_shift_unused_folios_left()\n\nThe function ceph_process_folio_batch() sets folio_batch entries to\nNULL, which is an illegal state.  Before folio_batch_release() crashes\ndue to this API violation, the function ceph_shift_unused_folios_left()\nis supposed to remove those NULLs from the array.\n\nHowever, since commit ce80b76dd327 (\"ceph: introduce\nceph_process_folio_batch() method\"), this shifting doesn't happen\nanymore because the \"for\" loop got moved to ceph_process_folio_batch(),\nand now the `i` variable that remains in ceph_writepages_start()\ndoesn't get incremented anymore, making the shifting effectively\nunreachable much of the time.\n\nLater, commit 1551ec61dc55 (\"ceph: introduce ceph_submit_write()\nmethod\") added more preconditions for doing the shift, replacing the\n`i` check (with something that is still just as broken):\n\n- if ceph_process_folio_batch() fails, shifting never happens\n\n- if ceph_move_dirty_page_in_page_array() was never called (because\n  ceph_process_folio_batch() has returned early for some of various\n  reasons), shifting never happens\n\n- if `processed_in_fbatch` is zero (because ceph_process_folio_batch()\n  has returned early for some of the reasons mentioned above or\n  because ceph_move_dirty_page_in_page_array() has failed), shifting\n  never happens\n\nSince those two commits, any problem in ceph_process_folio_batch()\ncould crash the kernel, e.g. this way:\n\n BUG: kernel NULL pointer dereference, address: 0000000000000034\n #PF: supervisor write access in kernel mode\n #PF: error_code(0x0002) - not-present page\n PGD 0 P4D 0\n Oops: Oops: 0002 [#1] SMP NOPTI\n CPU: 172 UID: 0 PID: 2342707 Comm: kworker\/u778:8 Not tainted 6.15.10-cm4all1-es #714 NONE\n Hardware name: Dell Inc. PowerEdge R7615\/0G9DHV, BIOS 1.6.10 12\/08\/2023\n Workqueue: writeback wb_workfn (flush-ceph-1)\n RIP: 0010:folios_put_refs+0x85\/0x140\n Code: 83 c5 01 39 e8 7e 76 48 63 c5 49 8b 5c c4 08 b8 01 00 00 00 4d 85 ed 74 05 41 8b 44 ad 00 48 8b 15 b0 >\n RSP: 0018:ffffb880af8db778 EFLAGS: 00010207\n RAX: 0000000000000001 RBX: 0000000000000000 RCX: 0000000000000003\n RDX: ffffe377cc3b0000 RSI: 0000000000000000 RDI: ffffb880af8db8c0\n RBP: 0000000000000000 R08: 000000000000007d R09: 000000000102b86f\n R10: 0000000000000001 R11: 00000000000000ac R12: ffffb880af8db8c0\n R13: 0000000000000000 R14: 0000000000000000 R15: ffff9bd262c97000\n FS:  0000000000000000(0000) GS:ffff9c8efc303000(0000) knlGS:0000000000000000\n CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n CR2: 0000000000000034 CR3: 0000000160958004 CR4: 0000000000770ef0\n PKRU: 55555554\n Call Trace:\n  <TASK>\n  ceph_writepages_start+0xeb9\/0x1410\n\nThe crash can be reproduced easily by changing the\nceph_check_page_before_write() return value to `-E2BIG`.\n\n(Interestingly, the crash happens only if `huge_zero_folio` has\nalready been allocated; without `huge_zero_folio`,\nis_huge_zero_folio(NULL) returns true and folios_put_refs() skips NULL\nentries instead of dereferencing them.  That makes reproducing the bug\nsomewhat unreliable.  See\nhttps:\/\/lore.kernel.org\/20250826231626.218675-1-max.kellermann@ionos.com\nfor a discussion of this detail.)\n\nMy suggestion is to move the ceph_shift_unused_folios_left() to right\nafter ceph_process_folio_batch() to ensure it always gets called to\nfix up the illegal folio_batch state."}],"metrics":{"cvssMetricV31":[{"source":"nvd@nist.gov","type":"Primary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1\/AV:L\/AC:L\/PR:L\/UI:N\/S:U\/C:N\/I:N\/A:H","baseScore":5.5,"baseSeverity":"MEDIUM","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"HIGH"},"exploitabilityScore":1.8,"impactScore":3.6},{"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1\/AV:L\/AC:L\/PR:L\/UI:N\/S:U\/C:N\/I:N\/A:H","baseScore":5.5,"baseSeverity":"MEDIUM","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"HIGH"},"exploitabilityScore":1.8,"impactScore":3.6}]},"weaknesses":[{"source":"nvd@nist.gov","type":"Primary","description":[{"lang":"en","value":"CWE-476"}]},{"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0","type":"Secondary","description":[{"lang":"en","value":"CWE-476"}]}],"configurations":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.15","versionEndExcluding":"6.16.8","matchCriteriaId":"4CDBA6F5-ADD5-4E49-89EE-9FA2364F2685"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:6.17:rc1:*:*:*:*:*:*","matchCriteriaId":"327D22EF-390B-454C-BD31-2ED23C998A1C"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:6.17:rc2:*:*:*:*:*:*","matchCriteriaId":"C730CD9A-D969-4A8E-9522-162AAF7C0EE9"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:6.17:rc3:*:*:*:*:*:*","matchCriteriaId":"39982C4B-716E-4B2F-8196-FA301F47807D"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:6.17:rc4:*:*:*:*:*:*","matchCriteriaId":"340BEEA9-D70D-4290-B502-FBB1032353B1"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:6.17:rc5:*:*:*:*:*:*","matchCriteriaId":"47E4C5C0-079F-4838-971B-8C503D48FCC2"}]}]}],"references":[{"url":"https:\/\/git.kernel.org\/stable\/c\/289b6615cf553d98509a9b273195d9936da1cfb2","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"]},{"url":"https:\/\/git.kernel.org\/stable\/c\/cce7c15faaac79b532a07ed6ab8332280ad83762","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"]}]}}]}