ceph: fix BUG_ON in __ceph_build_xattrs_blob() due to stale blob size
CVSS score
5.5
EPSS probability
%0.2
Risk score
0.0
Published
3 mo ago
Etkilenen ürün ve sürüm için yayımlanan güvenlik güncellemesini uygulayın.
Impact on My Inventory
Only the personal products you have added to your account are assessed; an organisation's inventory does not appear here.
Checking session…
Vulnerability description
DayBreach CVE AI Research
CVE-2026-52961 has vendor, distribution, patch and security-source records on file. We can compare them and prepare an explanation linked to the evidence.
In the Linux kernel, the following vulnerability has been resolved: ceph: fix BUG_ON in __ceph_build_xattrs_blob() due to stale blob size The generic/642 test-case can reproduce the kernel crash: [40243.605254] ------------[ cut here ]------------ [40243.605956] kernel BUG at fs/ceph/xattr.c:918! [40243.607142] Oops: invalid opcode: 0000 [#1] SMP PTI [40243.608067] CPU: 7 UID: 0 PID: 498762 Comm: kworker/7:1 Not tainted 7.0.0-rc7+ #3 PREEMPT(full) [40243.609700] Hardware name: QEMU Ubuntu 25.10 PC v2 (i440FX + PIIX, + 10.1 machine, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 [40243.611820] Workqueue: ceph-msgr ceph_con_workfn [40243.612715] RIP: 0010:__ceph_build_xattrs_blob+0x1b8/0x1e0 [40243.613731] Code: 0f 84 82 fe ff ff e9 cf 8e 56 ff 48 8d 65 e8 31 c0 5b 41 5c 41 5d 5d 31 d2 31 c9 31 f6 31 ff 45 31 c0 45 31 c9 c3 cc cc cc cc <0f> 0b 4c 8b 62 08 41 8b 85 24 07 00 00 49 83 c4 04 41 89 44 24 fc [40243.616888] RSP: 0018:ffffcc80c4d4b688 EFLAGS: 00010287 [40243.617773] RAX: 0000000000010026 RBX: 0000000000000001 RCX: 0000000000000000 [40243.618928] RDX: ffff8a773798dee0 RSI: 0000000000000000 RDI: 0000000000000000 [40243.620158] RBP: ffffcc80c4d4b6a0 R08: 0000000000000000 R09: 0000000000000000 [40243.621573] R10: 0000000000000000 R11: 0000000000000000 R12: ffff8a75f3b58000 [40243.622907] R13: ffff8a75f3b58000 R14: 0000000000000080 R15: 000000000000bffd [40243.624054] FS: 0000000000000000(0000) GS:ffff8a787d1b4000(0000) knlGS:0000000000000000 [40243.625331] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [40243.626269] CR2: 000072f390b623c0 CR3: 000000011c02a003 CR4: 0000000000372ef0 [40243.627408] Call Trace: [40243.627839] <TASK> [40243.628188] __prep_cap+0x3fd/0x4a0 [40243.628789] ? do_raw_spin_unlock+0x4e/0xe0 [40243.629474] ceph_check_caps+0x46a/0xc80 [40243.630094] ? __lock_acquire+0x4a2/0x2650 [40243.630773] ? find_held_lock+0x31/0x90 [40243.631347] ? handle_cap_grant+0x79f/0x1060 [40243.632068] ? lock_release+0xd9/0x300 [40243.632696] ? __mutex_unlock_slowpath+0x3e/0x340 [40243.633429] ? lock_release+0xd9/0x300 [40243.634052] handle_cap_grant+0xcf6/0x1060 [40243.634745] ceph_handle_caps+0x122b/0x2110 [40243.635415] mds_dispatch+0x5bd/0x2160 [40243.636034] ? ceph_con_process_message+0x65/0x190 [40243.636828] ? lock_release+0xd9/0x300 [40243.637431] ceph_con_process_message+0x7a/0x190 [40243.638184] ? kfree+0x311/0x4f0 [40243.638749] ? kfree+0x311/0x4f0 [40243.639268] process_message+0x16/0x1a0 [40243.639915] ? sg_free_table+0x39/0x90 [40243.640572] ceph_con_v2_try_read+0xf58/0x2120 [40243.641255] ? lock_acquire+0xc8/0x300 [40243.641863] ceph_con_workfn+0x151/0x820 [40243.642493] process_one_work+0x22f/0x630 [40243.643093] ? process_one_work+0x254/0x630 [40243.643770] worker_thread+0x1e2/0x400 [40243.644332] ? __pfx_worker_thread+0x10/0x10 [40243.645020] kthread+0x109/0x140 [40243.645560] ? __pfx_kthread+0x10/0x10 [40243.646125] ret_from_fork+0x3f8/0x480 [40243.646752] ? __pfx_kthread+0x10/0x10 [40243.647316] ? __pfx_kthread+0x10/0x10 [40243.647919] ret_from_fork_asm+0x1a/0x30 [40243.648556] </TASK> [40243.648902] Modules linked in: overlay hctr2 libpolyval chacha libchacha adiantum libnh libpoly1305 essiv intel_rapl_msr intel_rapl_common intel_uncore_frequency_common skx_edac_common nfit kvm_intel kvm irqbypass joydev ghash_clmulni_intel aesni_intel rapl input_leds mac_hid psmouse vga16fb serio_raw vgastate floppy i2c_piix4 pata_acpi bochs qemu_fw_cfg i2c_smbus sch_fq_codel rbd dm_crypt msr parport_pc ppdev lp parport efi_pstore [40243.654766] ---[ end trace 0000000000000000 ]--- Commit d93231a6bc8a ("ceph: prevent a client from exceeding the MDS maximum xattr size") moved the required_blob_size computation to before the __build_xattrs() call, introducing a race. __build_xattrs() releases and reacquires i_ceph_lock during execution. In that window, handle_cap_grant() may update i_xattrs.blob with a newer MDS-provided blob and bump i_xattrs.version. When __bui ---truncated---
IMPACT: Affected Products and Software
Affected Products
The following products are affected by CVE-2026-52961 vulnerability. Where our threat engine knows the exact affected versions, they are listed below.
RED HAT CSAF/VEX: Product Impact Check
SCORING: CVSS from Multiple Sources
CVSS Scores
The Common Vulnerability Scoring System is a standardised framework for assessing the severity of vulnerabilities in software and systems. We collect and display CVSS scores from several sources for each CVE.
| SCORE | VERSION | SEVERITY | VECTOR | SOURCE |
|---|---|---|---|---|
| 7.1 | CVSS 3.x | — | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H/E:U | Microsoft MSRC |
| 5.5 | CVSS V31 | MEDIUM | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H | NVD |
Patch and Remediation Guide
Solution & Remediation Advisory
5 doğrulanmış yama veya düzeltilmiş sürüm kanıtı bulundu.
Public exploit and active exploitation status
Verified exploit intelligence
No verified public PoC, exploit repository or Metasploit module has been found for this CVE yet.
Weakness Classification and Attack Patterns (CWE & CAPEC)
CWE - Common Weakness Enumeration
While CVE identifies specific instances of vulnerabilities, CWE categorises the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-52961 is associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-52961 weaknesses.
Attack Vector and Accessibility
Official Sources and Advisories
Similar Vulnerabilities
Get this vulnerability through the API
Affected products, version ranges, exploitation status and patch information in a single request, with a free key.
curl -H "x-api-key: $DAYBREACH_API_KEY" \ "https://api.daybreach.dev/api/v1/intel/cves/CVE-2026-52961"