LiveActive security incident?Get immediate response
CVE Record

CVE-2022-49879: ext4: fix BUG_ON() when directory entry has invalid rec_len

In the Linux kernel, the following vulnerability has been resolved: ext4: fix BUG_ON() when directory entry has invalid rec_len The rec_len field in the directory entry has to be a multiple of 4. A corrupted filesystem image can be used to hit a BUG() in ext4_rec_len_to_disk(), called from make_indexed_dir(). ------------[ cut here ]------------ kernel BUG at fs/ext4/ext4.h:2413! ... RIP: 0010:make_indexed_dir+0x53f/0x5f0 ... Call Trace: <TASK> ? add_dirent_to_buf+0x1b2/0x200 ext4_add_entry+0x36e/0x480 ext4_add_nondir+0x2b/0xc0 ext4_create+0x163/0x200 path_openat+0x635/0xe90 do_filp_open+0xb4/0x160 ? __create_object.isra.0+0x1de/0x3b0 ? _raw_spin_unlock+0x12/0x30 do_sys_openat2+0x91/0x150 __x64_sys_open+0x6c/0xa0 do_syscall_64+0x3c/0x80 entry_SYSCALL_64_after_hwframe+0x46/0xb0 The fix simply adds a call to ext4_check_dir_entry() to validate the directory entry, returning -EFSCORRUPTED if the entry is invalid.

UnknownCVSS not scoredNot KEV-listedUpdated
Discuss exposureBack to CVEs
Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

CVE-2022-49879 is a Linux kernel ext4 flaw where a corrupted directory entry in an ext4 filesystem can trigger a kernel BUG. The likely business impact is denial of service, such as a crash, when a vulnerable system processes a crafted or corrupted filesystem image.

Executive priority

Treat as a patch-management item with higher priority for fleets handling untrusted storage images or removable media. There is no cited evidence of active exploitation, but a kernel crash path can disrupt availability.

Technical view

The ext4 rec_len directory-entry field must be 4-byte aligned. In vulnerable kernels, invalid rec_len data can reach ext4_rec_len_to_disk() through make_indexed_dir(), triggering BUG_ON(). The fix adds ext4_check_dir_entry() validation and returns -EFSCORRUPTED for invalid entries.

Likely exposure

Exposure is most relevant on Linux systems using ext4 that mount or process corrupted or untrusted filesystem images, removable media, VM disks, or storage supplied by users. Standard servers that never handle untrusted ext4 media are less exposed, but still depend on kernel patch status.

Exploitation context

The source bundle does not show active exploitation, and KEV is false. The described trigger requires a corrupted filesystem image and vulnerable ext4 code path. No public source in the bundle supports remote exploitation or privilege escalation claims.

Researcher notes

The key behavior is validation of ext4 directory entries before converting rec_len for indexed directory creation. The provided records do not include CVSS, CWE, exploitability metrics, or detailed affected distro package ranges, so downstream vendor mapping is required.

Mitigation direction

  • Update to a vendor kernel containing the referenced stable ext4 fixes.
  • Follow Linux distribution advisories for backported kernel packages.
  • Avoid mounting untrusted ext4 filesystem images until patched.
  • Restrict removable media and user-supplied disk image handling on vulnerable systems.
  • Use filesystem corruption handling policies for suspicious ext4 media.

Validation and detection

  • Inventory Linux kernel versions on systems using ext4.
  • Check vendor advisories for CVE-2022-49879 backport status.
  • Confirm the ext4 fix or equivalent validation is present.
  • Identify workflows that mount user-supplied ext4 images or media.
  • Monitor for kernel BUG reports involving make_indexed_dir or ext4_rec_len_to_disk.
Prepared
Confidence
medium
Sources
7

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cve · low confidence lookup

CVE-2022-49879 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

Open ATT&CK lookup
Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
3Timeline events
0ADP providers
6Source links

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux3d0518f4758eca4339e75e5b9dbb7e06a5ce08b4, 3d0518f4758eca4339e75e5b9dbb7e06a5ce08b4, 3d0518f4758eca4339e75e5b9dbb7e06a5ce08b4, 3d0518f4758eca4339e75e5b9dbb7e06a5ce08b4, 3d0518f4758eca4339e75e5b9dbb7e06a5ce08b4unaffected
LinuxLinux2.6.30, 0, 5.4.224, 5.10.154, 5.15.78, 6.0.8, 6.1affected
Weakness

CWE details

No CWE listed

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.