CVE-2021-41133

HIGHNVD 8.88.8
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to NVD's CVSS score.

This high-severity CVE scores 8.8 under NVD CVSS v3. EPSS exploit probability: 0.4% (36th percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.

Triggered by: Headline CVSS from NVD CVSS v3
Sources: EPSS, NVD CVSS v3
Trending — 4 sources updated this week
8.8EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.4%CVSS: 8.8Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

Flatpak is a system for building, distributing, and running sandboxed desktop applications on Linux. In versions prior to 1.10.4 and 1.12.0, Flatpak apps with direct access to AF_UNIX sockets such as those used by Wayland, Pipewire or pipewire-pulse can trick portals and other host-OS services into treating the Flatpak app as though it was an ordinary, non-sandboxed host-OS process. They can do this by manipulating the VFS using recent mount-related syscalls that are not blocked by Flatpak's denylist seccomp filter, in order to substitute a crafted /.flatpak-info or make that file disappear entirely. Flatpak apps that act as clients for AF_UNIX sockets such as those used by Wayland, Pipewire or pipewire-pulse can escalate the privileges that the corresponding services will believe the Flatpak app has. Note that protocols that operate entirely over the D-Bus session bus (user bus), system bus or accessibility bus are not affected by this. This is due to the use of a proxy process xdg-dbus-proxy, whose VFS cannot be manipulated by the Flatpak app, when interacting with these buses. Patches exist for versions 1.10.4 and 1.12.0, and as of time of publication, a patch for version 1.8.2 is being planned. There are no workarounds aside from upgrading to a patched version.

CVSS v3
8.8
EG Score
8.8HIGHmedium confidence
EG Risk
40
EG Risk 40/100

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)
Severity88% × 45%
Impact severity (EG Severity): CVSS 8.8 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.4% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Track* at high (mission-essential systems).
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (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
0.4%
EPSS %ILE
36th
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 (8.8): severity, escalated by confirmed exploitation. This CVE's 8.8 is its impact severity (EG Severity), not escalated.

EG Severity
8.8 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.NVD CVSS v3 · CVSS v3.0 or v3.1
EG Likelihood
0.4% 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 (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (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 Vulnrichment) · Technical impact total (CISA Vulnrichment). 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

October 8, 2021

Last Modified

November 21, 2024

Advisory Details (10)

Auto-updated Jul 30, 2026
Patch available. Sources: github_commit, github.
GitHub advisoryMentions a patch (unverified)

CVE-2021-41133: Sandbox bypass via recent VFS-manipulating syscalls · Advisory · flatpak/flatpak · GitHub

https://github.com/flatpak/flatpak/security/advisories/GHSA-67h7-w3jq-vh4q
GitHub commit Patch Available

commit e26ac7586c39 (flatpak/flatpak)

Patch available: flatpak/flatpak 1.14.5 (contains commit e26ac7586c39)

https://github.com/flatpak/flatpak/commit/e26ac7586c392b5eb35ff4609fe232c52523b2cf
GitHub commit Patch Available

commit a10f52a7565c (flatpak/flatpak)

Patch available: flatpak/flatpak 1.14.5 (contains commit a10f52a7565c)

https://github.com/flatpak/flatpak/commit/a10f52a7565c549612c92b8e736a6698a53db330
GitHub commit Patch Available

commit 9766ee05b142 (flatpak/flatpak)

Patch available: flatpak/flatpak 1.14.5 (contains commit 9766ee05b142)

https://github.com/flatpak/flatpak/commit/9766ee05b1425db397d2cf23afd24c7f6146a69f
GitHub commit Patch Available

commit 89ae9fe74c6d (flatpak/flatpak)

Patch available: flatpak/flatpak 1.14.5 (contains commit 89ae9fe74c6d)

https://github.com/flatpak/flatpak/commit/89ae9fe74c6d445bb1b3a40e568d77cf5de47e48
GitHub commit Patch Available

commit 4c34815784e9 (flatpak/flatpak)

Patch available: flatpak/flatpak 1.14.5 (contains commit 4c34815784e9)

https://github.com/flatpak/flatpak/commit/4c34815784e9ffda5733225c7d95824f96375e36
GitHub commit Patch Available

commit 462fca2c666e (flatpak/flatpak)

Patch available: flatpak/flatpak 1.14.5 (contains commit 462fca2c666e)

https://github.com/flatpak/flatpak/commit/462fca2c666e0cd2b60d6d2593a7216a83047aaf
GitHub commit Patch Available

commit 26b12484eb8a (flatpak/flatpak)

Patch available: flatpak/flatpak 1.14.5 (contains commit 26b12484eb8a)

https://github.com/flatpak/flatpak/commit/26b12484eb8a6219b9e7aa287b298a894b2f34ca
GitHub commit Patch Available

commit 1330662f33a5 (flatpak/flatpak)

Patch available: flatpak/flatpak 1.14.5 (contains commit 1330662f33a5)

https://github.com/flatpak/flatpak/commit/1330662f33a55e88bfe18e76de28b7922d91a999
Web page

oss-security - WebKitGTK and WPE WebKit Security Advisory WSA-2021-0006

http://www.openwall.com/lists/oss-security/2021/10/26/9

Vendor Advisories for CVE-2021-41133(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 / EcosystemFix (by version range) / PatchReleasedSource
ubuntuflatpak-tests (1.10.2-1ubuntu1.1) @ hirsute2026-10-21ubuntu
redhatflatpak-0:1.0.9-5.el8_12021-11-02redhat
redhatflatpak-0:1.6.2-6.el8_22021-11-02redhat
redhatflatpak-0:1.8.5-4.el8_42021-11-01redhat
redhatflatpak-0:1.0.9-12.el7_92021-11-01redhat

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

(4 across 4 ecosystems)
Debian:11(1)
PackageVulnerable rangeFix by version rangeDependents
flatpak1.10.2-3, 1.10.3-0+deb11u1, 1.10.3-0+deb11u1~bpo11+1, 1.10.5-0+deb11u1~bpo10+1
  • every version up to 1.10.5-0+deb11u1: fixed in 1.10.5-0+deb11u1
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
flatpak—
  • every version up to 1.12.1-1: fixed in 1.12.1-1
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
flatpak—
  • every version up to 1.12.1-1: fixed in 1.12.1-1
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
flatpak—
  • every version up to 1.12.1-1: fixed in 1.12.1-1
—

Weakness Classification(1)

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

Additional Vendor Advisories

(4)

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 11× 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 204 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 109 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-23 16:28 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  2. 2026-10-22 16:29 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  3. 2026-10-21 16:28 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  4. 2026-10-21 09:00 UTCEG score recompute
  5. 2026-10-21 09:00 UTCVendor advisory
  6. 2026-10-20 16:28 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  7. 2026-10-19 16:28 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  8. 2026-10-18 16:28 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  9. 2026-10-18 08:54 UTCEG score recompute
  10. 2026-10-17 20:55 UTCOSV refresh
  11. 2026-10-17 16:29 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  12. 2026-10-16 16:34 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  13. 2026-10-15 16:28 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  14. 2026-10-14 16:29 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  15. 2026-10-13 16:28 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  16. 2026-10-12 19:10 UTCEG score recompute
  17. 2026-10-12 16:30 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  18. 2026-10-11 23:35 UTCEG score recompute
  19. 2026-10-11 13:44 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  20. 2026-10-10 19:56 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  21. 2026-10-09 20:04 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  22. 2026-10-08 16:40 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  23. 2026-10-07 23:45 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  24. 2026-10-06 15:14 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  25. 2026-10-05 17:40 UTCEPSS rescoreEPSS 0.4% · 35th percentile
Show 70 more
  1. 2026-10-04 23:19 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  2. 2026-10-03 14:22 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  3. 2026-10-02 16:23 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  4. 2026-10-01 19:46 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  5. 2026-09-30 15:41 UTCEG score recompute
  6. 2026-09-30 15:00 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  7. 2026-09-29 15:15 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  8. 2026-09-28 13:47 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  9. 2026-09-27 13:41 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  10. 2026-09-26 15:54 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  11. 2026-09-26 00:21 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  12. 2026-09-25 15:45 UTCOSV refresh
  13. 2026-09-24 14:00 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  14. 2026-09-23 13:44 UTCEPSS rescoreEPSS 0.4% · 37th percentile
  15. 2026-09-22 14:44 UTCEPSS rescoreEPSS 0.4% · 37th percentile
  16. 2026-09-21 20:28 UTCEPSS rescoreEPSS 0.4% · 37th percentile
  17. 2026-09-20 20:13 UTCEPSS rescoreEPSS 0.4% · 37th percentile
  18. 2026-09-19 15:38 UTCEPSS rescoreEPSS 0.4% · 37th percentile
  19. 2026-09-18 19:23 UTCEPSS rescoreEPSS 0.4% · 37th percentile
  20. 2026-09-17 19:23 UTCEPSS rescoreEPSS 0.4% · 37th percentile
  21. 2026-09-16 14:05 UTCEPSS rescoreEPSS 0.4% · 37th percentile
  22. 2026-09-15 03:06 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  23. 2026-09-12 14:57 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  24. 2026-09-11 14:49 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  25. 2026-09-11 09:33 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  26. 2026-09-08 21:56 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  27. 2026-09-07 15:58 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  28. 2026-09-06 13:45 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  29. 2026-09-06 06:22 UTCOSV refresh
  30. 2026-09-05 15:25 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  31. 2026-09-04 13:57 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  32. 2026-09-04 05:03 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  33. 2026-09-02 14:09 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  34. 2026-09-01 13:50 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  35. 2026-09-01 03:33 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  36. 2026-08-30 19:14 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  37. 2026-08-30 01:19 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  38. 2026-08-28 21:37 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  39. 2026-08-27 14:22 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  40. 2026-08-26 14:43 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  41. 2026-08-25 13:46 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  42. 2026-08-24 14:13 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  43. 2026-08-23 00:16 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  44. 2026-08-21 23:46 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  45. 2026-08-20 22:52 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  46. 2026-08-19 17:26 UTCOSV refresh
  47. 2026-08-19 17:01 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  48. 2026-08-18 13:45 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  49. 2026-08-17 13:44 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  50. 2026-08-16 14:53 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  51. 2026-08-16 02:11 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  52. 2026-08-15 01:27 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  53. 2026-08-13 21:57 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  54. 2026-08-12 13:48 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  55. 2026-08-11 13:38 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  56. 2026-08-09 13:44 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  57. 2026-08-08 16:33 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  58. 2026-08-07 16:24 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  59. 2026-08-06 13:44 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  60. 2026-08-05 19:14 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  61. 2026-08-04 12:57 UTCOSV refresh
  62. 2026-08-04 10:34 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  63. 2026-08-03 10:33 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  64. 2026-08-02 02:24 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  65. 2026-08-01 04:13 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  66. 2026-07-30 16:25 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  67. 2026-07-30 01:28 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  68. 2026-07-28 15:33 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  69. 2026-07-26 14:52 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  70. 2026-07-25 14:15 UTCEPSS rescoreEPSS 0.4% · 33rd percentile

Frequently asked(5)

What is CVE-2021-41133?
CVE-2021-41133 is a high-severity vulnerability; its CVE record was published on October 8, 2021. Flatpak is a system for building, distributing, and running sandboxed desktop applications on Linux. In versions prior to 1.10.4 and 1.12.0, Flatpak apps with direct access to AFUNIX sockets such as those used by Wayland, Pipewire or pipewire-pulse can trick portals and other host-OS services into…
When was the CVE record for CVE-2021-41133 published?
The CVE record for CVE-2021-41133 was published on October 8, 2021. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of November 21, 2024; the record at its source may have been updated since.
Is CVE-2021-41133 actively exploited?
CVE-2021-41133 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.4% probability of exploitation in the next 30 days (36th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2021-41133?
CVE-2021-41133 has a CVSS v3 base score of 8.8 (NVD).
How do I remediate CVE-2021-41133?
A fix for CVE-2021-41133 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2021-41133 are linked in the Vendor Advisories panel on this page.

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