CVE-2021-47958

MEDIUMNVD 4.34.3
EchelonGraph scoreMEDIUM confidence

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

Score 4.3 from GitHub Security Advisory published 2026-05-15. NVD baseline CVSS 4.3; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, NVD CVSS v3
Elevated
4.3EG
EchelonGraph verdictPlan mitigationRemediate within your standard update timelines (the SSVC decision on this page).
  • CISA's Vulnrichment rates exploitation as PoC; EchelonGraph holds no exploit-code reference for it
CISA-KEV: Not listedEPSS PROB: 0.2%CVSS: 4.3Exploit: No code on recordExposed services: Not assessed

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

CouchCMS 2.2.1 contains a server-side request forgery vulnerability that allows authenticated attackers to make arbitrary HTTP requests by uploading malicious SVG files. Attackers can upload SVG files containing external entity references through the browse.php endpoint to access internal services and resources.

CVSS v3
4.3
EG Score
4.3MEDIUMmedium confidence
EG Risk
35
EG Risk 35/100

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 (value × EchelonGraph’s weight)
Severity43% × 45%
The EG Score, 4.3 of 10.
Exploitation40% × 40%
EchelonGraph's fixed weight for EG-KEV Tier 3 (Elevated): a constant, not a probability.
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 public PoC (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: No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines, and watch the vendor's advisory for the fix.
EPSS PROB
0.2%
EPSS %ILE
13th
KEV
Not listed

SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Track* at high (mission-essential systems).

No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines, and watch the vendor's advisory for the fix.

Exploitation public PoC (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.

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

May 15, 2026

Last Modified

May 18, 2026

Advisory Details (3)

Auto-updated Jun 26, 2026
No fix on record yet.
Web page

CouchCMS 2.2.1 Server-Side Request Forgery via SVG upload | Advisories | VulnCheck

https://www.vulncheck.com/advisories/couchcms-server-side-request-forgery-via-svg-upload
Web page

CouchCMS 2.2.1 - Server-Side Request Forgery - PHP webapps Exploit

https://www.exploit-db.com/exploits/49675
Web page

GitHub - CouchCMS/CouchCMS: Simple Open-Source CMS for designers · GitHub

https://github.com/CouchCMS/CouchCMS

Vendor Advisories for CVE-2021-47958(1)

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

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 8× in last 7d / 28× 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 97 of 262 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. 3 repeat rows among the latest 100 are merged into the row they repeat. The 165 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-12 19:04 UTCEG score recompute
  2. 2026-10-12 16:30 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  3. 2026-10-11 23:30 UTCEG score recompute
  4. 2026-10-10 19:56 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  5. 2026-10-09 20:04 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  6. 2026-10-08 16:40 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  7. 2026-10-07 23:45 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  8. 2026-10-06 15:14 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  9. 2026-10-05 17:40 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  10. 2026-10-04 23:19 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  11. 2026-10-03 14:22 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  12. 2026-10-02 16:23 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  13. 2026-09-30 15:46 UTCEG score recompute
  14. 2026-09-30 15:00 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  15. 2026-09-29 15:15 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  16. 2026-09-28 13:47 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  17. 2026-09-26 15:54 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  18. 2026-09-26 00:21 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  19. 2026-09-24 14:00 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  20. 2026-09-23 13:45 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  21. 2026-09-22 14:44 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  22. 2026-09-21 20:28 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  23. 2026-09-20 20:13 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  24. 2026-09-19 15:38 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  25. 2026-09-18 19:24 UTCEPSS rescoreEPSS 0.2% · 15th percentile
Show 72 more
  1. 2026-09-17 19:23 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  2. 2026-09-16 14:05 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  3. 2026-09-15 03:06 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  4. 2026-09-12 14:57 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  5. 2026-09-11 14:49 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  6. 2026-09-11 09:33 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  7. 2026-09-08 21:57 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  8. 2026-09-07 15:58 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  9. 2026-09-06 13:45 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  10. 2026-09-05 15:25 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  11. 2026-09-04 13:57 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  12. 2026-09-04 05:03 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  13. 2026-09-02 14:09 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  14. 2026-09-01 13:51 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  15. 2026-08-30 19:14 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  16. 2026-08-30 01:19 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  17. 2026-08-28 21:38 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  18. 2026-08-27 14:22 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  19. 2026-08-26 14:43 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  20. 2026-08-24 14:13 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  21. 2026-08-23 17:27 UTCEG score recompute
  22. 2026-08-23 17:27 UTCGHSA enrichmentGHSA-c329-4cx6-v738 · GitHub CVSS 4.3
  23. 2026-08-22 01:29 UTCEG score recompute
  24. 2026-08-22 01:29 UTCGHSA enrichmentGHSA-c329-4cx6-v738 · GitHub CVSS 4.3
  25. 2026-08-21 23:46 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  26. 2026-08-20 22:52 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  27. 2026-08-20 19:24 UTCEG score recompute
  28. 2026-08-20 19:24 UTCGHSA enrichmentGHSA-c329-4cx6-v738 · GitHub CVSS 4.3
  29. 2026-08-19 17:01 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  30. 2026-08-18 13:45 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  31. 2026-08-17 13:44 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  32. 2026-08-17 10:15 UTCEG score recompute
  33. 2026-08-17 10:15 UTCGHSA enrichmentGHSA-c329-4cx6-v738 · GitHub CVSS 4.3
  34. 2026-08-16 14:53 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  35. 2026-08-16 03:49 UTCEG score recompute
  36. 2026-08-16 03:49 UTCGHSA enrichmentGHSA-c329-4cx6-v738 · GitHub CVSS 4.3
  37. 2026-08-16 02:11 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  38. 2026-08-15 01:27 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  39. 2026-08-15 01:21 UTCGHSA enrichmentGHSA-c329-4cx6-v738 · GitHub CVSS 4.3
  40. 2026-08-14 02:18 UTCEG score recompute
  41. 2026-08-14 02:18 UTCGHSA enrichmentGHSA-c329-4cx6-v738 · GitHub CVSS 4.3
  42. 2026-08-13 21:57 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  43. 2026-08-12 22:54 UTCEG score recompute
  44. 2026-08-12 22:54 UTCGHSA enrichmentGHSA-c329-4cx6-v738 · GitHub CVSS 4.3
  45. 2026-08-12 13:48 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  46. 2026-08-11 23:50 UTCEG score recompute
  47. 2026-08-11 23:50 UTCGHSA enrichmentGHSA-c329-4cx6-v738 · GitHub CVSS 4.3
  48. 2026-08-11 13:38 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  49. 2026-08-11 00:47 UTCEG score recompute
  50. 2026-08-11 00:47 UTCGHSA enrichmentGHSA-c329-4cx6-v738 · GitHub CVSS 4.3
  51. 2026-08-10 00:48 UTCEG score recompute
  52. 2026-08-10 00:48 UTCGHSA enrichmentGHSA-c329-4cx6-v738 · GitHub CVSS 4.3
  53. 2026-08-09 13:44 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  54. 2026-08-09 01:45 UTCEG score recompute
  55. 2026-08-09 01:45 UTCGHSA enrichmentGHSA-c329-4cx6-v738 · GitHub CVSS 4.3
  56. 2026-08-08 16:34 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  57. 2026-08-07 19:37 UTCEG score recompute
  58. 2026-08-07 19:37 UTCGHSA enrichmentGHSA-c329-4cx6-v738 · GitHub CVSS 4.3
  59. 2026-08-07 16:24 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  60. 2026-08-06 20:34 UTCEG score recompute
  61. 2026-08-06 20:34 UTCGHSA enrichmentGHSA-c329-4cx6-v738 · GitHub CVSS 4.3
  62. 2026-08-06 13:44 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  63. 2026-08-05 21:30 UTCEG score recompute
  64. 2026-08-05 21:30 UTCGHSA enrichmentGHSA-c329-4cx6-v738 · GitHub CVSS 4.3
  65. 2026-08-05 19:15 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  66. 2026-08-04 15:06 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  67. 2026-08-04 10:34 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  68. 2026-08-03 18:55 UTCGHSA enrichmentGHSA-c329-4cx6-v738 · GitHub CVSS 4.3
  69. 2026-08-02 17:59 UTCEG score recompute
  70. 2026-08-02 17:59 UTCGHSA enrichmentGHSA-c329-4cx6-v738 · GitHub CVSS 4.3
  71. 2026-08-02 02:24 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  72. 2026-08-01 18:55 UTCEG score recompute

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2021-47958?
CVE-2021-47958 is a medium-severity vulnerability; its CVE record was published on May 15, 2026. CouchCMS 2.2.1 contains a server-side request forgery vulnerability that allows authenticated attackers to make arbitrary HTTP requests by uploading malicious SVG files. Attackers can upload SVG files containing external entity references through the browse.php endpoint to access internal services…
When was CVE-2021-47958 made public?
CVE-2021-47958 was made public on January 25, 2021: that is the date its CVE record's CNA, VulnCheck, gives for when the vulnerability was made public. The CVE record itself was published on May 15, 2026. EchelonGraph's copy of the record carries a last-modified date of May 18, 2026; the record at its source may have been updated since.
Is CVE-2021-47958 actively exploited?
CVE-2021-47958 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.2% probability of exploitation in the next 30 days (13th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2021-47958?
CVE-2021-47958 has a CVSS v3 base score of 4.3 (NVD).
How do I remediate CVE-2021-47958?
No fix for CVE-2021-47958 is confirmed yet. Until one is published, restrict network exposure of the affected system or apply the vendor's mitigation — for example, keep it off the internet or limit it to trusted networks — and watch the vendor's advisory for the fix. The vendor advisories EchelonGraph has for CVE-2021-47958 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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