CVE-2021-3782

CRITICALNVD 6.69.8
EchelonGraph scoreMEDIUM confidence

“▲” beside the score: it is higher than NVD's CVSS score.

Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2022-09-25. NVD baseline CVSS 6.6; sources differ by 3.2.

Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, NVD CVSS v3

Also known asEUVD-2021-27046 (ENISA EUVD) · GHSA-pvw2-9h4r-c5cr (GitHub Security Advisories)Source: ENISA EUVD

9.8EG
EchelonGraph verdictMonitorRemediate within your standard update timelines (the SSVC decision on this page).
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.3%CVSS: 6.6Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

An internal reference count is held on the buffer pool, incremented every time a new buffer is created from the pool. The reference count is maintained as an int; on LP64 systems this can cause the reference count to overflow if the client creates a large number of wl_shm buffer objects, or if it can coerce the server to create a large number of external references to the buffer storage. With the reference count overflowing, a use-after-free can be constructed on the wl_shm_pool tracking structure, where values may be incremented or decremented; it may also be possible to construct a limited oracle to leak 4 bytes of server-side memory to the attacking client at a time.

CVSS v3
6.6
EG Score
9.8CRITICALmedium confidence
EG Risk
44
EG Risk 44/100

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)
Severity98% × 45%
Impact severity (EG Severity): CVSS 9.8 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.3% × 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 every mission impact level.
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (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
0.3%
EPSS %ILE
24th
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 (9.8): severity, escalated by confirmed exploitation. This CVE's 9.8 is its impact severity (EG Severity), not escalated.

EG Severity
9.8 CRITICALCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
0.3% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-11-12). 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 every mission impact level.CISA BOD 26-04: 60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track at every mission impact level.

A fix is available. Apply it within your standard update timelines.

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (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)60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact partial (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

September 23, 2022

Last Modified

May 22, 2025

Advisory Details (1)

Auto-updated Oct 15, 2026
Patch available.
Web page

Reference count overflow in shm leads to use-after-free (#224) · Issues · wayland / wayland · GitLab

https://gitlab.freedesktop.org/wayland/wayland/-/issues/224

Vendor Advisories for CVE-2021-3782(2)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(3)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
ubuntulibwayland-client0 (1.12.0-1~ubuntu16.04.3+esm1) @ xenial2026-11-12ubuntu
ubuntulibwayland-client0 (1.16.0-1ubuntu1.1~18.04.4) @ bionic2026-11-12ubuntu
redhatwayland-0:1.21.0-1.el82023-05-16redhat

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
wayland1.18.0-2~exp1.1 ... 1.26.0-1 (19 versions)
  • every version on: no fix on record
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
wayland—
  • every version up to 1.21.0-1: fixed in 1.21.0-1
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
wayland—
  • every version up to 1.21.0-1: fixed in 1.21.0-1
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
wayland—
  • every version up to 1.21.0-1: fixed in 1.21.0-1
—

Weakness Classification(1)

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

Additional Vendor Advisories

(2)

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 21× in last 7d / 90× 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 its CVE.org record (CNA or CISA ADP). 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). "EchelonGraph re-scored" is our own recompute of this CVE's score, not an update from a source, and is not counted in the refreshes above. Most recent first.

Showing the most recent 100 of 319 rows 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. None are among the latest 100 rows. The 219 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-11-13 16:41 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  2. 2026-11-13 02:52 UTCEchelonGraph re-scored
  3. 2026-11-13 02:52 UTCVendor advisory
  4. 2026-11-13 02:52 UTCGHSA enrichmentGHSA-pvw2-9h4r-c5cr · GitHub severity CRITICAL · GitHub CVSS 9.8
  5. 2026-11-12 16:29 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  6. 2026-11-12 02:04 UTCEchelonGraph re-scored
  7. 2026-11-12 02:04 UTCVendor advisory
  8. 2026-11-12 02:04 UTCGHSA enrichmentGHSA-pvw2-9h4r-c5cr · GitHub severity CRITICAL · GitHub CVSS 9.8
  9. 2026-11-11 16:31 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  10. 2026-11-11 01:15 UTCEchelonGraph re-scored
  11. 2026-11-11 01:15 UTCVendor advisory
  12. 2026-11-11 01:15 UTCGHSA enrichmentGHSA-pvw2-9h4r-c5cr · GitHub severity CRITICAL · GitHub CVSS 9.8
  13. 2026-11-10 16:35 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  14. 2026-11-10 00:22 UTCEchelonGraph re-scored
  15. 2026-11-10 00:22 UTCVendor advisory
  16. 2026-11-10 00:22 UTCGHSA enrichmentGHSA-pvw2-9h4r-c5cr · GitHub severity CRITICAL · GitHub CVSS 9.8
  17. 2026-11-09 16:29 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  18. 2026-11-08 23:36 UTCEchelonGraph re-scored
  19. 2026-11-08 23:36 UTCVendor advisory
  20. 2026-11-08 23:36 UTCGHSA enrichmentGHSA-pvw2-9h4r-c5cr · GitHub severity CRITICAL · GitHub CVSS 9.8
  21. 2026-11-08 16:33 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  22. 2026-11-07 22:49 UTCEchelonGraph re-scored
  23. 2026-11-07 22:49 UTCVendor advisory
  24. 2026-11-07 22:49 UTCGHSA enrichmentGHSA-pvw2-9h4r-c5cr · GitHub severity CRITICAL · GitHub CVSS 9.8
  25. 2026-11-07 16:34 UTCEPSS rescoreEPSS 0.3% · 24th percentile
Show 75 more
  1. 2026-11-06 22:01 UTCEchelonGraph re-scored
  2. 2026-11-06 22:01 UTCVendor advisory
  3. 2026-11-06 22:01 UTCGHSA enrichmentGHSA-pvw2-9h4r-c5cr · GitHub severity CRITICAL · GitHub CVSS 9.8
  4. 2026-11-06 16:30 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  5. 2026-11-05 21:14 UTCEchelonGraph re-scored
  6. 2026-11-05 21:14 UTCVendor advisory
  7. 2026-11-05 21:14 UTCGHSA enrichmentGHSA-pvw2-9h4r-c5cr · GitHub severity CRITICAL · GitHub CVSS 9.8
  8. 2026-11-05 16:31 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  9. 2026-11-04 20:28 UTCEchelonGraph re-scored
  10. 2026-11-04 20:28 UTCVendor advisory
  11. 2026-11-04 20:28 UTCGHSA enrichmentGHSA-pvw2-9h4r-c5cr · GitHub severity CRITICAL · GitHub CVSS 9.8
  12. 2026-11-04 16:30 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  13. 2026-11-03 19:39 UTCEchelonGraph re-scored
  14. 2026-11-03 19:39 UTCVendor advisory
  15. 2026-11-03 19:39 UTCGHSA enrichmentGHSA-pvw2-9h4r-c5cr · GitHub severity CRITICAL · GitHub CVSS 9.8
  16. 2026-11-03 19:25 UTCOSV refresh
  17. 2026-11-03 16:38 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  18. 2026-11-02 18:53 UTCEchelonGraph re-scored
  19. 2026-11-02 18:53 UTCVendor advisory
  20. 2026-11-02 18:53 UTCGHSA enrichmentGHSA-pvw2-9h4r-c5cr · GitHub severity CRITICAL · GitHub CVSS 9.8
  21. 2026-11-02 16:37 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  22. 2026-11-01 18:06 UTCEchelonGraph re-scored
  23. 2026-11-01 18:06 UTCVendor advisory
  24. 2026-11-01 18:06 UTCGHSA enrichmentGHSA-pvw2-9h4r-c5cr · GitHub severity CRITICAL · GitHub CVSS 9.8
  25. 2026-11-01 16:29 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  26. 2026-10-31 17:19 UTCEchelonGraph re-scored
  27. 2026-10-31 17:19 UTCVendor advisory
  28. 2026-10-31 17:19 UTCGHSA enrichmentGHSA-pvw2-9h4r-c5cr · GitHub severity CRITICAL · GitHub CVSS 9.8
  29. 2026-10-31 16:29 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  30. 2026-10-30 16:33 UTCEchelonGraph re-scored
  31. 2026-10-30 16:33 UTCVendor advisory
  32. 2026-10-30 16:33 UTCGHSA enrichmentGHSA-pvw2-9h4r-c5cr · GitHub severity CRITICAL · GitHub CVSS 9.8
  33. 2026-10-30 16:30 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  34. 2026-10-29 16:29 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  35. 2026-10-29 15:45 UTCEchelonGraph re-scored
  36. 2026-10-29 15:45 UTCVendor advisory
  37. 2026-10-29 15:45 UTCGHSA enrichmentGHSA-pvw2-9h4r-c5cr · GitHub severity CRITICAL · GitHub CVSS 9.8
  38. 2026-10-28 16:28 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  39. 2026-10-28 14:56 UTCEchelonGraph re-scored
  40. 2026-10-28 14:56 UTCVendor advisory
  41. 2026-10-28 14:56 UTCGHSA enrichmentGHSA-pvw2-9h4r-c5cr · GitHub severity CRITICAL · GitHub CVSS 9.8
  42. 2026-10-27 16:28 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  43. 2026-10-27 13:47 UTCEchelonGraph re-scored
  44. 2026-10-27 13:47 UTCVendor advisory
  45. 2026-10-27 13:46 UTCGHSA enrichmentGHSA-pvw2-9h4r-c5cr · GitHub severity CRITICAL · GitHub CVSS 9.8
  46. 2026-10-26 16:28 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  47. 2026-10-26 12:27 UTCVendor advisory
  48. 2026-10-26 12:27 UTCGHSA enrichmentGHSA-pvw2-9h4r-c5cr · GitHub severity CRITICAL · GitHub CVSS 9.8
  49. 2026-10-25 18:24 UTCEchelonGraph re-scored
  50. 2026-10-25 16:28 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  51. 2026-10-25 11:35 UTCEchelonGraph re-scored
  52. 2026-10-25 11:35 UTCVendor advisory
  53. 2026-10-25 11:35 UTCGHSA enrichmentGHSA-pvw2-9h4r-c5cr · GitHub severity CRITICAL · GitHub CVSS 9.8
  54. 2026-10-24 16:29 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  55. 2026-10-24 10:47 UTCEchelonGraph re-scored
  56. 2026-10-24 10:47 UTCVendor advisory
  57. 2026-10-24 10:47 UTCGHSA enrichmentGHSA-pvw2-9h4r-c5cr · GitHub severity CRITICAL · GitHub CVSS 9.8
  58. 2026-10-23 16:28 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  59. 2026-10-23 10:00 UTCEchelonGraph re-scored
  60. 2026-10-23 10:00 UTCVendor advisory
  61. 2026-10-23 10:00 UTCGHSA enrichmentGHSA-pvw2-9h4r-c5cr · GitHub severity CRITICAL · GitHub CVSS 9.8
  62. 2026-10-22 16:29 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  63. 2026-10-22 09:13 UTCEchelonGraph re-scored
  64. 2026-10-22 09:13 UTCVendor advisory
  65. 2026-10-22 09:13 UTCGHSA enrichmentGHSA-pvw2-9h4r-c5cr · GitHub severity CRITICAL · GitHub CVSS 9.8
  66. 2026-10-21 16:28 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  67. 2026-10-21 08:24 UTCEchelonGraph re-scored
  68. 2026-10-21 08:24 UTCVendor advisory
  69. 2026-10-21 08:24 UTCGHSA enrichmentGHSA-pvw2-9h4r-c5cr · GitHub severity CRITICAL · GitHub CVSS 9.8
  70. 2026-10-20 16:28 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  71. 2026-10-20 07:37 UTCEchelonGraph re-scored
  72. 2026-10-20 07:37 UTCVendor advisory
  73. 2026-10-20 07:37 UTCGHSA enrichmentGHSA-pvw2-9h4r-c5cr · GitHub severity CRITICAL · GitHub CVSS 9.8
  74. 2026-10-19 16:28 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  75. 2026-10-19 06:49 UTCEchelonGraph re-scored

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Debian:11:wayland

Frequently asked(5)

What is CVE-2021-3782?
CVE-2021-3782 is a critical-severity vulnerability; its CVE record was published on September 23, 2022. An internal reference count is held on the buffer pool, incremented every time a new buffer is created from the pool. The reference count is maintained as an int; on LP64 systems this can cause the reference count to overflow if the client creates a large number of wl_shm buffer objects, or if it…
When was the CVE record for CVE-2021-3782 published?
The CVE record for CVE-2021-3782 was published on September 23, 2022. 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 May 22, 2025; the record at its source may have been updated since.
Is CVE-2021-3782 actively exploited?
CVE-2021-3782 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.3% probability of exploitation in the next 30 days (24th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2021-3782?
CVE-2021-3782 has a CVSS v3 base score of 6.6 (NVD). EchelonGraph synthesises NVD + FIRST EPSS + GHSA into a combined EG score of 9.8 (CRITICAL).
How do I remediate CVE-2021-3782?
A fix for CVE-2021-3782 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2021-3782 are linked in the Vendor Advisories panel on this page.

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