squashfs_opendir in unsquash-2.c in Squashfs-Tools 4.5 allows Directory Traversal, a different vulnerability than CVE-2021-40153. A squashfs filesystem that has been crafted to include a symbolic link and then contents under the same filename in a filesystem can cause unsquashfs to first create the symbolic link pointing outside the expected directory, and then the subsequent write operation will cause the unsquashfs process to write through the symbolic link elsewhere in the filesystem.
CVE-2021-41072
“—” beside the score: it is equal to NVD's CVSS score.
Score 8.1 from GitHub Security Advisory (severity: HIGH) published 2022-05-24. NVD baseline CVSS 8.1; sources differ by 0.0.
- High severity, but no confirmed exploitation yet
A fix is available — apply it.
- CVSS v3
- 8.1
- EG Score
- 8.1HIGHmedium confidence
- EG Risk
- 37EG Risk 37/100
EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.
How it’s computed (value × EchelonGraph’s weight)Severity81% × 45%Impact severity (EG Severity): CVSS 8.1 of 10. Never the KEV-floored or EPSS-lifted EG Score.Exploitation2.3% × 40%FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.Automatability0% × 15%CISA's BOD 26-04 default: no one has published Automatable for this CVE, and CISA treats it as “no” for a CVE not in KEV.SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Track* at high (mission-essential systems).Exploitation none (no CISA value, KEV listing or exploit code on record) · Automatable no (CISA's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). EchelonGraph holds no SSVC assessment of this CVE from CISA: none of these inputs is from Vulnrichment. EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.Action: A fix is available. Apply it within your standard update timelines. - EPSS PROB
- 2.3%
- EPSS %ILE
- 83rd
- KEV
- Not listed
What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)
The EG score (8.1): severity, escalated by confirmed exploitation. This CVE's 8.1 is its impact severity (EG Severity), not escalated.
- EG Severity
- 8.1 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
- EG Likelihood
- 2.3% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-20). FIRST's exploitation probability, not an EchelonGraph model.
- Confirmed exploitation
- None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
- EG Priority
- SSVC Track at medium mission impactTrack at low or medium mission impact; Track* at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source: the SSVC and BOD 26-04 blocks below.
SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Track* at high (mission-essential systems).
A fix is available. Apply it within your standard update timelines.
Exploitation none (no CISA value, KEV listing or exploit code on record) · Automatable no (CISA's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). EchelonGraph holds no SSVC assessment of this CVE from CISA: none of these inputs is from Vulnrichment. EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table
BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.
In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). Where an input reads “CISA's BOD 26-04 default”, no one has published it for this CVE, and CISA's implementation guidance says: “If “Automatable” and “Technical Impact” information items about a CVE ID are not available and the CVE ID is not in the KEV Catalog, CISA will treat its values as “no” and “total,” respectively, until CISA or a third party provides metadata about the CVE ID. CISA will always provide the Vulnrichment data for a CVE ID listed in the KEV Catalog.” Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it
Published
September 14, 2021
Last Modified
November 21, 2024
Advisory Details (5)
Auto-updated Sep 17, 2026[SECURITY] [DSA 4987-1] squashfs-tools security update
https://www.debian.org/security/2021/dsa-4987squashfs-tools: Multiple Vulnerabilities (GLSA 202305-29) — Gentoo security
https://security.gentoo.org/glsa/202305-29[SECURITY] [DLA 2789-1] squashfs-tools security update
https://lists.debian.org/debian-lts-announce/2021/10/msg00017.htmlunsquashfs - unvalidated filepaths allow writing outside of destination · Issue #72 · plougher/squashfs-tools · GitHub
https://github.com/plougher/squashfs-tools/issues/72#issuecomment-913833405commit e0485802ec72 (plougher/squashfs-tools)
Patch available: plougher/squashfs-tools 4.5.1 (contains commit e0485802ec72)
https://github.com/plougher/squashfs-tools/commit/e0485802ec72996c20026da320650d8362f555bdVendor Advisories for CVE-2021-41072(1)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Patch Availability(5)
| Vendor / Ecosystem | Fix (by version range) / Patch | Released | Source |
|---|---|---|---|
| ubuntu | squashfs-tools (1:4.4-2ubuntu0.2) @ hirsute | 2026-10-21 | ubuntu |
| ubuntu | squashfs-tools (1:4.3-3ubuntu2.16.04.3+esm1) @ xenial | 2026-10-21 | ubuntu |
| ubuntu | squashfs-tools (1:4.4-2ubuntu0.3) @ hirsute | 2026-10-21 | ubuntu |
| redhat | squashfs-tools-0:4.3-21.el8 | 2024-05-22 | redhat |
| redhat | squashfs-tools-0:4.4-10.git1.el9 | 2024-04-30 | redhat |
Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.
Affected Packages
(17 across 17 ecosystems)
Alpine:v3.14(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| squashfs-tools | — |
| — |
Alpine:v3.15(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| squashfs-tools | — |
| — |
Alpine:v3.16(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| squashfs-tools | — |
| — |
Alpine:v3.17(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| squashfs-tools | — |
| — |
Alpine:v3.18(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| squashfs-tools | — |
| — |
Alpine:v3.19(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| squashfs-tools | — |
| — |
Alpine:v3.20(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| squashfs-tools | — |
| — |
Alpine:v3.21(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| squashfs-tools | — |
| — |
Alpine:v3.22(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| squashfs-tools | — |
| — |
Alpine:v3.23(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| squashfs-tools | — |
| — |
Alpine:v3.24(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| squashfs-tools | — |
| — |
Debian:10(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| squashfs-tools | 1:4.3-12, 1:4.3-12+deb10u1 |
| — |
Debian:11(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| squashfs-tools | 1:4.4-2, 1:4.4-2+deb11u1 |
| — |
Debian:12(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| squashfs-tools | — |
| — |
Debian:13(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| squashfs-tools | — |
| — |
Debian:14(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| squashfs-tools | — |
| — |
Debian:9(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| squashfs-tools | 1:4.3-3, 1:4.3-3+deb9u1, 1:4.3-3+deb9u2 |
| — |
Weakness Classification(2)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Additional Vendor Advisories
(5)
Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.
Data Freshness Timeline
(refreshed 12× in last 7d / 38× in last 30d)
Each row is a time one of our pipelines fetched, updated or re-scored this CVE. 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. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.
Showing the most recent 95 of 199 refreshes on record for this CVE.
A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. 5 repeat rows among the latest 100 are merged into the row they repeat. The 104 oldest rows on record are not shown and were not checked, so the counts can still include repeats.
- 2026-10-23 16:28 UTCEPSS rescoreEPSS 2.3% · 83rd percentile
- 2026-10-22 16:29 UTCEPSS rescoreEPSS 2.3% · 83rd percentile
- 2026-10-21 16:28 UTCEPSS rescoreEPSS 2.3% · 83rd percentile
- 2026-10-21 09:00 UTCEG score recompute
- 2026-10-21 09:00 UTCVendor advisory
- 2026-10-21 09:00 UTCGHSA enrichmentGHSA-f6m6-9fjw-69qm · GitHub severity HIGH · GitHub CVSS 8.1
- 2026-10-20 16:28 UTCEPSS rescoreEPSS 2.3% · 83rd percentile
- 2026-10-19 16:28 UTCEPSS rescoreEPSS 2.3% · 83rd percentile
- 2026-10-18 16:28 UTCEPSS rescoreEPSS 2.3% · 82nd percentile
- 2026-10-18 08:54 UTCEG score recompute
- 2026-10-18 00:25 UTCOSV refresh
- 2026-10-17 16:29 UTCEPSS rescoreEPSS 2.3% · 82nd percentile
- 2026-10-16 16:34 UTCEPSS rescoreEPSS 2.3% · 82nd percentile
- 2026-10-15 16:28 UTCEPSS rescoreEPSS 2.3% · 82nd percentile
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- 2026-10-13 16:28 UTCEPSS rescoreEPSS 2.3% · 82nd percentile
- 2026-10-12 19:10 UTCEG score recompute
- 2026-10-12 16:30 UTCEPSS rescoreEPSS 2.3% · 82nd percentile
- 2026-10-11 23:35 UTCEG score recompute
- 2026-10-11 13:44 UTCEPSS rescoreEPSS 2.3% · 82nd percentile
- 2026-10-10 19:56 UTCEPSS rescoreEPSS 2.3% · 82nd percentile
- 2026-10-09 20:04 UTCEPSS rescoreEPSS 2.3% · 82nd percentile
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- 2026-10-07 23:45 UTCEPSS rescoreEPSS 2.3% · 82nd percentile
- 2026-10-06 15:14 UTCEPSS rescoreEPSS 2.3% · 82nd percentile
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- 2026-10-05 17:40 UTCEPSS rescoreEPSS 2.3% · 82nd percentile
- 2026-10-03 14:22 UTCEPSS rescoreEPSS 2.3% · 82nd percentile
- 2026-10-02 16:23 UTCEPSS rescoreEPSS 2.3% · 82nd percentile
- 2026-10-01 19:46 UTCEPSS rescoreEPSS 2.3% · 82nd percentile
- 2026-09-30 15:41 UTCEG score recompute
- 2026-09-30 15:00 UTCEPSS rescoreEPSS 2.3% · 82nd percentile
- 2026-09-29 15:15 UTCEPSS rescoreEPSS 2.3% · 82nd percentile
- 2026-09-28 13:47 UTCEPSS rescoreEPSS 2.3% · 82nd percentile
- 2026-09-27 13:41 UTCEPSS rescoreEPSS 2.3% · 82nd percentile
- 2026-09-26 15:54 UTCEPSS rescoreEPSS 2.3% · 82nd percentile
- 2026-09-26 00:21 UTCEPSS rescoreEPSS 2.3% · 82nd percentile
- 2026-09-25 17:45 UTCOSV refresh
- 2026-09-24 14:00 UTCEPSS rescoreEPSS 2.3% · 82nd percentile
- 2026-09-23 13:44 UTCEPSS rescoreEPSS 2.3% · 82nd percentile
- 2026-09-22 14:44 UTCEPSS rescoreEPSS 2.3% · 82nd percentile
- 2026-09-21 20:28 UTCEPSS rescoreEPSS 2.3% · 82nd percentile
- 2026-09-20 20:13 UTCEPSS rescoreEPSS 2.3% · 82nd percentile
- 2026-09-19 15:38 UTCEPSS rescoreEPSS 2.3% · 82nd percentile
- 2026-09-18 19:23 UTCEPSS rescoreEPSS 2.3% · 82nd percentile
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- 2026-09-16 14:05 UTCEPSS rescoreEPSS 2.3% · 82nd percentile
- 2026-09-15 03:06 UTCEPSS rescoreEPSS 2.3% · 82nd percentile
- 2026-09-12 14:57 UTCEPSS rescoreEPSS 2.3% · 82nd percentile
- 2026-09-11 14:49 UTCEPSS rescoreEPSS 2.3% · 82nd percentile
- 2026-09-11 09:33 UTCEPSS rescoreEPSS 2.3% · 82nd percentile
- 2026-09-08 21:56 UTCEPSS rescoreEPSS 2.3% · 82nd percentile
- 2026-09-07 15:58 UTCEPSS rescoreEPSS 2.3% · 82nd percentile
- 2026-09-06 13:45 UTCEPSS rescoreEPSS 2.3% · 82nd percentile
- 2026-09-06 08:30 UTCOSV refresh
- 2026-09-05 15:25 UTCEPSS rescoreEPSS 2.3% · 81st percentile
- 2026-09-04 13:57 UTCEPSS rescoreEPSS 2.3% · 82nd percentile
- 2026-09-04 05:03 UTCEPSS rescoreEPSS 2.3% · 82nd percentile
- 2026-09-02 14:09 UTCEPSS rescoreEPSS 2.3% · 82nd percentile
- 2026-09-01 13:50 UTCEPSS rescoreEPSS 2.3% · 82nd percentile
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- 2026-08-30 19:14 UTCEPSS rescoreEPSS 2.3% · 82nd percentile
- 2026-08-30 01:19 UTCEPSS rescoreEPSS 2.3% · 81st percentile
- 2026-08-28 21:37 UTCEPSS rescoreEPSS 2.3% · 81st percentile
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- 2026-08-26 14:43 UTCEPSS rescoreEPSS 2.3% · 81st percentile
- 2026-08-25 13:46 UTCEPSS rescoreEPSS 2.3% · 81st percentile
- 2026-08-24 14:13 UTCEPSS rescoreEPSS 2.3% · 81st percentile
- 2026-08-23 00:16 UTCEPSS rescoreEPSS 2.3% · 81st percentile
- 2026-08-21 23:46 UTCEPSS rescoreEPSS 2.3% · 81st percentile
- 2026-08-20 22:52 UTCEPSS rescoreEPSS 2.3% · 81st percentile
- 2026-08-19 18:34 UTCOSV refresh
- 2026-08-19 17:01 UTCEPSS rescoreEPSS 2.3% · 81st percentile
- 2026-08-18 13:45 UTCEPSS rescoreEPSS 2.3% · 81st percentile
- 2026-08-17 13:44 UTCEPSS rescoreEPSS 2.3% · 81st percentile
- 2026-08-16 14:53 UTCEPSS rescoreEPSS 2.3% · 81st percentile
- 2026-08-16 02:11 UTCEPSS rescoreEPSS 2.3% · 81st percentile
- 2026-08-15 01:27 UTCEPSS rescoreEPSS 2.3% · 81st percentile
- 2026-08-13 21:57 UTCEPSS rescoreEPSS 2.3% · 81st percentile
- 2026-08-12 13:48 UTCEPSS rescoreEPSS 2.3% · 81st percentile
- 2026-08-11 13:38 UTCEPSS rescoreEPSS 2.3% · 81st percentile
- 2026-08-09 13:44 UTCEPSS rescoreEPSS 2.3% · 81st percentile
- 2026-08-08 16:33 UTCEPSS rescoreEPSS 2.3% · 81st percentile
- 2026-08-07 16:24 UTCEPSS rescoreEPSS 2.3% · 81st percentile
- 2026-08-06 13:44 UTCEPSS rescoreEPSS 2.3% · 81st percentile
- 2026-08-05 19:14 UTCEPSS rescoreEPSS 2.3% · 81st percentile
- 2026-08-04 14:29 UTCOSV refresh
- 2026-08-04 10:34 UTCEPSS rescoreEPSS 2.3% · 81st percentile
- 2026-08-03 10:33 UTCEPSS rescoreEPSS 2.3% · 81st percentile
- 2026-08-02 02:24 UTCEPSS rescoreEPSS 2.3% · 81st percentile
- 2026-08-01 04:13 UTCEPSS rescoreEPSS 2.3% · 81st percentile
- 2026-07-30 16:25 UTCEPSS rescoreEPSS 2.3% · 81st percentile
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- 2026-07-28 15:33 UTCEPSS rescoreEPSS 2.3% · 81st percentile
- 2026-07-26 14:52 UTCEPSS rescoreEPSS 2.3% · 81st percentile
- 2026-07-25 14:15 UTCEPSS rescoreEPSS 2.3% · 81st percentile
Related CVEs(same product + same vendor + same CWE)
Same product
5 shownAlpine:v3.14:squashfs-tools · Debian:11:squashfs-tools
Same CWE
10 shownCWE-22 · CWE-59
- CVE-2021-37200NVD 7.7EG 7.9EPSS p99HIGH
- CVE-2021-40357EG 4.9MEDIUM
- CVE-2021-37532EG 4.3MEDIUM
- CVE-2021-38163EG 9.9 KEVEPSS p99CRITICAL
- CVE-2021-40444NVD 7.8EG 9.0 KEVEPSS p100CRITICAL
- CVE-2021-40964EG 6.5EPSS p95MEDIUM
- CVE-2021-39208EG 4.3MEDIUM
- CVE-2021-38360EG 8.3HIGH
- CVE-2021-31843NVD 7.3EG 7.8HIGH
- CVE-2021-3806EG 5.3MEDIUM
Frequently asked(5)
What is CVE-2021-41072?
When was the CVE record for CVE-2021-41072 published?
Is CVE-2021-41072 actively exploited?
What is the CVSS score of CVE-2021-41072?
How do I remediate CVE-2021-41072?
Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by CVE-2021-41072
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