Goal Reached Thanks to every supporter — we hit 100%!

Goal: 1000 CNY · Raised: 1359 CNY

100%
Buy Us a Coffee

CVE-2026-80808— ext4: stop retrying saturated xattr cache entries

Quick assessment

Affected
Linux Linux
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Linux kernel是美国Linux基金会开源的一个操作系统内核。 Linux kernel存在安全漏洞，该漏洞源于ext4文件系统对xattr缓存条目引用计数处理不当，饱和条目重试时未标记不可用，导致无限循环并阻塞并发rmdir调用，攻击者可能通过损坏的文件系统造成系统挂起，从而引发拒绝服务。

AI Predicted 7.5 Difficulty: Hard EPSS 0.19% · P9

Possible ATT&CK Techniques 1 AI

T1499 · Endpoint Denial of Service

Affected Version Matrix 30

VendorProduct Version RangeStatus
Linux Linux 1a56cd972ce121b6cf2517a47a578782bbd2ec95< 119a2f053242ed75bdd2ebc95baf3ae7db6ccacf affected
1be97463696c7291a3e1547614e96432b0bd3add< 61631352a5b405c89be579de00903b72e6888aa4 affected
65f8b80053a1b2fd602daa6814e62d6fa90e5e9b< 8865cd664484517703df5c18a965dc3227572b87 affected
65f8b80053a1b2fd602daa6814e62d6fa90e5e9b< a40c45268f4358207aa9c53764fed2e05f62986a affected
65f8b80053a1b2fd602daa6814e62d6fa90e5e9b< 889ec86464d261f026f6c334040cfc6c58c99d58 affected
65f8b80053a1b2fd602daa6814e62d6fa90e5e9b< 4902a5cba21aeaf91e6b29e20e0967a5f6abdcd9 affected
65f8b80053a1b2fd602daa6814e62d6fa90e5e9b< 55ee6533c1db7f7656fa8dd19637f3f8b8c08dc5 affected
65f8b80053a1b2fd602daa6814e62d6fa90e5e9b< dbd4aea175ad3c46436acb251e817b4374628072 affected
… +22 more rows
Get alerts for future matching vulnerabilities Log in to subscribe

I. Basic Information for CVE-2026-80808

Vulnerability Information
Have questions about the vulnerability? See if Shenlong's analysis helps!
View Shenlong Deep Dive ↗

Although we use advanced large model technology, its output may still contain inaccurate or outdated information.Shenlong tries to ensure data accuracy, but please verify and judge based on the actual situation.

Vulnerability Title
ext4: stop retrying saturated xattr cache entries
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: ext4: stop retrying saturated xattr cache entries ext4_xattr_block_set() retries when a cache entry selected for reuse has a saturated reference count after taking the buffer lock. The retry returns to the mbcache lookup without making that entry ineligible, so it can select the same unusable entry indefinitely. A task spinning there can hold the parent directory's i_rwsem and leave concurrent rmdir callers blocked. Normally a reusable entry has a reference count below EXT4_XATTR_REFCOUNT_MAX because the count and MBE_REUSABLE_B are updated under the same buffer lock. A corrupted filesystem can violate that invariant. The syzbot reproducer reports allocator and xattr corruption before triggering this retry loop. Check the untrusted on-disk count before incrementing it, avoiding overflow, and clear MBE_REUSABLE_B when it is already saturated. The next lookup then skips the entry that was just proven unusable. This mirrors the normal transition at EXT4_XATTR_REFCOUNT_MAX; the release path marks the entry reusable again on the exact 1024-to-1023 transition. Using the same QEMU harness and guest parameters, current unpatched Linux hung in 6 of 8 420-second trials with the do_rmdir signature; representative NMI backtraces caught the owner spinning in ext4_xattr_block_set(). The patched kernel completed 28 of 28 trials without a hung-task report; the final twelve trials exercised the reviewed overflow-safe form of the change. syzbot's patch testing also completed without reproducing the hang.
Source: CVE Program / CVE List V5
CVSS Information
N/A
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5
Vulnerability Title
Linux kernel 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Linux kernel是美国Linux基金会开源的一个操作系统内核。 Linux kernel存在安全漏洞，该漏洞源于ext4文件系统对xattr缓存条目引用计数处理不当，饱和条目重试时未标记不可用，导致无限循环并阻塞并发rmdir调用，攻击者可能通过损坏的文件系统造成系统挂起，从而引发拒绝服务。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
Linux Linux 1a56cd972ce121b6cf2517a47a578782bbd2ec95 ~ 119a2f053242ed75bdd2ebc95baf3ae7db6ccacf -
Linux Linux 6.0 -

II. Public POCs for CVE-2026-80808

# POC Description Source Link Shenlong Link
AI-Generated POC Premium

No public POC found.

Login to generate AI POC

III. Intelligence Information for CVE-2026-80808

请登录查看更多情报信息。

Patches & Fixes for CVE-2026-80808 (9)

Same Patch Batch · Linux · 2026-09-04 · 156 CVEs total

CVE-2026-80865 bpf: Add missing access_ok call to copy_user_syms
CVE-2026-80856 fuse: fix invalidate lock leak on setattr writeback failure
CVE-2026-80857 fuse: wait for FR_FINISHED on abort_on_kill to prevent use-after-free
CVE-2026-80858 fuse: publish io-uring queues with release semantics
CVE-2026-80859 fuse: fix missing barrier when checking io-uring readiness
CVE-2026-80860 fuse: fix race between interrupt and resend
CVE-2026-80861 usb: xhci: bail out of setup if the controller is inaccessible
CVE-2026-80862 nvme-tcp: fix usage of page_frag_cache
CVE-2026-80863 RDMA/rxe: Fix OOB in free_rd_atomic_resources()
CVE-2026-80864 RDMA/rxe: Fix responder UAF on IB_QP_MAX_DEST_RD_ATOMIC modify_qp
CVE-2026-80870 drm/amdkfd: Validate CRIU-restored IDs before idr_alloc
CVE-2026-80874 arm64: dts: renesas: ironhide: Describe inline ECC carveouts
CVE-2026-80873 KVM: arm64: nv: Write ESR_EL2 for injected nested SError exceptions
CVE-2026-80872 ALSA: hda/tas2781: Cancel async firmware request at unbind
CVE-2026-80871 crypto: xilinx-trng - Remove crypto_rng interface
CVE-2026-80868 ntfs3: Allocate iomap inline_data using alloc_page
CVE-2026-80866 tipc: avoid busy looping in tipc_exit_net()
CVE-2026-80867 alpha/PCI: Add security_locked_down() check to pci_mmap_resource()
CVE-2026-80855 fuse: fix invalidate lock leak on open O_TRUNC DAX failure
CVE-2026-80869 ntfs: bound the attribute-list entry in ntfs_read_inode_mount()

Showing top 20 of 156 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

V. Comments for CVE-2026-80808

No comments yet

Leave a comment