CVE-2021-33477

HIGHNVD 8.88.8—
EchelonGraph scoreMEDIUM confidence

Score 8.8 from GitHub Security Advisory (severity: HIGH) published 2022-05-24. NVD baseline CVSS 8.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
8.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 4%CVSS: 8.8Exploit: None knownExposed: 0

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

rxvt-unicode 9.22, rxvt 2.7.10, mrxvt 0.5.4, and Eterm 0.9.7 allow (potentially remote) code execution because of improper handling of certain escape sequences (ESC G Q). A response is terminated by a newline.

CVSS v3
8.8
EG Score
8.8(medium)
EG Risk
46(Track)
EG Risk 46/100SSVC: 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
Severity88% × 45%
Exploitation4% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
4%
EPSS %ILE
90%
KEV
Not listed

Published

May 20, 2021

Last Modified

November 21, 2024

Advisory Details (8)

Auto-updated Aug 9, 2026
Patch available.
generic

[SECURITY] Fedora 34 Update: mrxvt-0.5.3-31.fc34 - package-announce - Fedora mailing-lists

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/DUV4LDVZVW7KCGPAMFZD4ZJ4FVLPOX4C/
generic

[SECURITY] Fedora 33 Update: mrxvt-0.5.3-31.fc33 - package-announce - Fedora mailing-lists

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/AO52OLNOOKOCZSJCN3R7Q25XA32BWNWP/
generic

[SECURITY] Fedora 34 Update: rxvt-unicode-9.26-1.fc34 - package-announce - Fedora mailing-lists

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/6RFMU5YXXNYYVA7G2DAHRXXHO6JKVFUT/
generic Patch Available

[SECURITY] [DLA 2683-1] rxvt security update

https://lists.debian.org/debian-lts-announce/2021/06/msg00012.html
generic Patch Available

[SECURITY] [DLA 2682-1] mrxvt security update

https://lists.debian.org/debian-lts-announce/2021/06/msg00011.html
generic Patch Available

[SECURITY] [DLA 2681-1] eterm security update

https://lists.debian.org/debian-lts-announce/2021/06/msg00010.html
generic Patch Available

[SECURITY] [DLA 2671-1] rxvt-unicode security update

https://lists.debian.org/debian-lts-announce/2021/05/msg00026.html
generic

[ViewVC] Log of: cvs/rxvt-unicode/Changes

http://cvs.schmorp.de/rxvt-unicode/Changes?view=log

Affected Packages

(15 across 7 ecosystems)
Debian:9(4)
PackageVulnerable rangeFixed inDependents
eterm0.9.6-50.9.6-5+deb9u1—
mrxvt0.5.4-20.5.4-2+deb9u1—
rxvt1:2.7.10-7, 1:2.7.10-7+deb9u11:2.7.10-7+deb9u2—
rxvt-unicode9.22-19.22-1+deb9u1—
Alpine:v3.10(2)
PackageVulnerable rangeFixed inDependents
mrxvt—0.5.4-r8—
rxvt-unicode—9.22-r7—
Alpine:v3.11(2)
PackageVulnerable rangeFixed inDependents
mrxvt—0.5.4-r8—
rxvt-unicode—9.22-r8—
Debian:11(2)
PackageVulnerable rangeFixed inDependents
eterm—0.9.6-6.1—
rxvt-unicode—9.22-11—
Debian:12(2)
PackageVulnerable rangeFixed inDependents
eterm—0.9.6-6.1—
rxvt-unicode—9.22-11—
Debian:14(2)
PackageVulnerable rangeFixed inDependents
eterm0.7-1 ... 0.9.6-6 (23 versions)0.9.6-6.1—
rxvt-unicode—9.22-11—
Debian:13(1)
PackageVulnerable rangeFixed inDependents
rxvt-unicode—9.22-11—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 8× in last 7d / 33× 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 163 total refreshes for this CVE.

  1. 2026-09-19 15:38 UTCEPSS rescore
  2. 2026-09-18 19:23 UTCEPSS rescore
  3. 2026-09-17 19:23 UTCEPSS rescore
  4. 2026-09-17 19:23 UTCEPSS rescore
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  9. 2026-09-12 14:57 UTCEPSS rescore
  10. 2026-09-11 14:49 UTCEPSS rescore
  11. 2026-09-11 09:33 UTCEPSS rescore
  12. 2026-09-08 21:56 UTCEPSS rescore
  13. 2026-09-07 15:58 UTCEPSS rescore
  14. 2026-09-06 17:01 UTCOSV refresh
  15. 2026-09-06 13:45 UTCEPSS rescore
  16. 2026-09-06 13:45 UTCEPSS rescore
  17. 2026-09-05 15:25 UTCEPSS rescore
  18. 2026-09-04 13:57 UTCEPSS rescore
  19. 2026-09-04 05:03 UTCEPSS rescore
  20. 2026-09-02 14:08 UTCEPSS rescore
  21. 2026-09-01 13:50 UTCEPSS rescore
  22. 2026-09-01 03:32 UTCEPSS rescore
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  24. 2026-08-30 01:19 UTCEPSS rescore
  25. 2026-08-30 01:19 UTCEPSS rescore
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  1. 2026-08-28 21:37 UTCEPSS rescore
  2. 2026-08-27 14:22 UTCEPSS rescore
  3. 2026-08-26 14:42 UTCEPSS rescore
  4. 2026-08-25 13:46 UTCEPSS rescore
  5. 2026-08-24 14:13 UTCEPSS rescore
  6. 2026-08-23 00:16 UTCEPSS rescore
  7. 2026-08-21 23:46 UTCEPSS rescore
  8. 2026-08-20 22:52 UTCEPSS rescore
  9. 2026-08-20 02:45 UTCOSV refresh
  10. 2026-08-19 17:01 UTCEPSS rescore
  11. 2026-08-18 13:45 UTCEPSS rescore
  12. 2026-08-17 13:44 UTCEPSS rescore
  13. 2026-08-16 14:53 UTCEPSS rescore
  14. 2026-08-16 02:11 UTCEPSS rescore
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  16. 2026-08-15 01:27 UTCEPSS rescore
  17. 2026-08-13 21:57 UTCEPSS rescore
  18. 2026-08-12 13:48 UTCEPSS rescore
  19. 2026-08-11 13:38 UTCEPSS rescore
  20. 2026-08-09 13:44 UTCEPSS rescore
  21. 2026-08-08 16:33 UTCEPSS rescore
  22. 2026-08-07 16:24 UTCEPSS rescore
  23. 2026-08-06 13:43 UTCEPSS rescore
  24. 2026-08-05 19:14 UTCEPSS rescore
  25. 2026-08-04 21:48 UTCOSV refresh
  26. 2026-08-04 15:06 UTCEPSS rescore
  27. 2026-08-04 10:34 UTCEPSS rescore
  28. 2026-08-03 10:33 UTCEPSS rescore
  29. 2026-08-02 02:24 UTCEPSS rescore
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  31. 2026-08-01 04:13 UTCEPSS rescore
  32. 2026-07-30 16:25 UTCEPSS rescore
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  37. 2026-07-25 14:15 UTCEPSS rescore
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  39. 2026-07-23 14:16 UTCEPSS rescore
  40. 2026-07-23 14:16 UTCEPSS rescore
  41. 2026-07-23 02:01 UTCEG score recompute
  42. 2026-07-22 22:48 UTCEG score recompute
  43. 2026-07-22 14:06 UTCEPSS rescore
  44. 2026-07-22 14:06 UTCEPSS rescore
  45. 2026-07-21 15:22 UTCEPSS rescore
  46. 2026-07-21 15:22 UTCEPSS rescore
  47. 2026-07-20 17:05 UTCEPSS rescore
  48. 2026-07-19 14:29 UTCEPSS rescore
  49. 2026-07-19 14:29 UTCEPSS rescore
  50. 2026-07-19 02:27 UTCEPSS rescore
  51. 2026-07-18 19:59 UTCOSV refresh
  52. 2026-07-18 10:02 UTCEPSS rescore
  53. 2026-07-18 10:02 UTCEPSS rescore
  54. 2026-07-16 17:00 UTCEPSS rescore
  55. 2026-07-16 17:00 UTCEPSS rescore
  56. 2026-07-15 16:55 UTCEPSS rescore
  57. 2026-07-15 01:58 UTCEPSS rescore
  58. 2026-07-13 22:27 UTCEPSS rescore
  59. 2026-07-13 06:10 UTCEPSS rescore
  60. 2026-07-12 05:44 UTCEPSS rescore
  61. 2026-07-12 05:44 UTCEPSS rescore
  62. 2026-07-11 08:25 UTCEPSS rescore
  63. 2026-07-11 08:25 UTCEPSS rescore
  64. 2026-07-09 19:07 UTCEPSS rescore
  65. 2026-07-08 15:12 UTCEPSS rescore
  66. 2026-07-06 16:25 UTCEPSS rescore
  67. 2026-07-06 02:21 UTCEPSS rescore
  68. 2026-07-05 02:28 UTCEPSS rescore
  69. 2026-07-05 02:28 UTCEPSS rescore
  70. 2026-07-04 06:29 UTCEPSS rescore
  71. 2026-07-04 06:29 UTCEPSS rescore
  72. 2026-07-01 15:04 UTCEPSS rescore
  73. 2026-07-01 03:18 UTCOSV refresh
  74. 2026-06-30 23:20 UTCEPSS rescore
  75. 2026-06-30 23:20 UTCEPSS rescore

Frequently asked(5)

What is CVE-2021-33477?
CVE-2021-33477 is a high vulnerability published on May 20, 2021. rxvt-unicode 9.22, rxvt 2.7.10, mrxvt 0.5.4, and Eterm 0.9.7 allow (potentially remote) code execution because of improper handling of certain escape sequences (ESC G Q). A response is terminated by a newline.
When was CVE-2021-33477 disclosed?
CVE-2021-33477 was first published in the National Vulnerability Database on May 20, 2021, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-33477 actively exploited?
CVE-2021-33477 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 4% probability of exploitation in the next 30 days, which ranks it in the top 9.7% of all scored CVEs.
What is the CVSS score of CVE-2021-33477?
CVE-2021-33477 has a CVSS v3 base score of 8.8 (NVD).
How do I remediate CVE-2021-33477?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-33477, 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.

Dependency Blast Radius

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