CVE-2021-47406

MEDIUMNVD 5.55.5
EchelonGraph scoreMEDIUM confidence

Score 5.5 from GitHub Security Advisory published 2024-05-21. NVD baseline CVSS 5.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
5.5
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 5.5Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

In the Linux kernel, the following vulnerability has been resolved:

ext4: add error checking to ext4_ext_replay_set_iblocks()

If the call to ext4_map_blocks() fails due to an corrupted file system, ext4_ext_replay_set_iblocks() can get stuck in an infinite loop. This could be reproduced by running generic/526 with a file system that has inline_data and fast_commit enabled. The system will repeatedly log to the console:

EXT4-fs warning (device dm-3): ext4_block_to_path:105: block 1074800922 > max in inode 131076

and the stack that it gets stuck in is:

ext4_block_to_path+0xe3/0x130 ext4_ind_map_blocks+0x93/0x690 ext4_map_blocks+0x100/0x660 skip_hole+0x47/0x70 ext4_ext_replay_set_iblocks+0x223/0x440 ext4_fc_replay_inode+0x29e/0x3b0 ext4_fc_replay+0x278/0x550 do_one_pass+0x646/0xc10 jbd2_journal_recover+0x14a/0x270 jbd2_journal_load+0xc4/0x150 ext4_load_journal+0x1f3/0x490 ext4_fill_super+0x22d4/0x2c00

With this patch, generic/526 still fails, but system is no longer locking up in a tight loop. It's likely the root casue is that fast_commit replay is corrupting file systems with inline_data, and we probably need to add better error handling in the fast commit replay code path beyond what is done here, which essentially just breaks the infinite loop without reporting the to the higher levels of the code.

CVSS v3
5.5
EG Score
5.5(medium)
EG Risk
25(Track)
EG Risk 25/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity55% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS
16.4%
KEV
Not listed

Published

May 21, 2024

Last Modified

April 2, 2025

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 13× in last 7d / 51× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 103 total refreshes for this CVE.

  1. 2026-07-23 14:16 UTCEPSS rescore
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Frequently asked(5)

What is CVE-2021-47406?
CVE-2021-47406 is a medium vulnerability published on May 21, 2024. In the Linux kernel, the following vulnerability has been resolved: ext4: add error checking to ext4extreplaysetiblocks() If the call to ext4mapblocks() fails due to an corrupted file system, ext4extreplaysetiblocks() can get stuck in an infinite loop. This could be reproduced by running…
When was CVE-2021-47406 disclosed?
CVE-2021-47406 was first published in the National Vulnerability Database on May 21, 2024, with the most recent update on April 2, 2025. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-47406 actively exploited?
CVE-2021-47406 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 16.4% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2021-47406?
CVE-2021-47406 has a CVSS v3 base score of 5.5 (NVD).
How do I remediate CVE-2021-47406?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-47406, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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