CVE-2009-2055

CRITICALNVD 5.99.0
EchelonGraph scoreHIGH confidence

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

Score elevated to 9.0 because this CVE is listed on the CISA Known Exploited Vulnerabilities catalog (added 2022-03-25), indicating real-world exploitation has been confirmed by US federal agencies. NVD baseline CVSS 5.9 retained for reference. Confidence: HIGH.

Triggered by: CISA KEV (actively exploited)
Sources: CISA Known Exploited Vulnerabilities catalog, EPSS, GitHub Security Advisory, NVD CVSS v3
Trending — 3 sources updated this weekExploited in the wild
9.0EG
EchelonGraph verdictMitigate nowTreat as an emergency — this is being exploited.
  • Actively exploited in the wild (CISA-KEV) — the reason this is sooner than the SSVC decision on this page at every mission impact level
CISA-KEV: ExploitedEPSS PROB: 3.3%CVSS: 5.9Exploit: No code on recordExposed services: Not assessed

A fix is referenced (a reference tagged "Patch", often a source commit), but no release containing it is confirmed — find the release that contains it; until it is applied, mitigate (WAF / firewall / segmentation).

Cisco IOS XR 3.4.0 through 3.8.1 allows remote attackers to cause a denial of service (session reset) via a BGP UPDATE message with an invalid attribute, as demonstrated in the wild on 17 August 2009.

CVSS v3
5.9
EG Score
9.0CRITICALhigh confidence
EG Risk
81
EG Risk 81/100

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)
Severity90% × 45%
The EG Score, 9.0 of 10.
Exploitation100% × 40%
Fixed at 100% for a CISA KEV listing: EchelonGraph's rule.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Attend at high (mission-essential systems).
Exploitation active (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 referenced, but no release containing it is confirmed. Check the referenced fix and the vendor's advisory for a release that contains it and apply that within your standard update timelines at low or medium mission impact and sooner than that at high; until then, restrict network exposure of the affected system or apply the vendor's mitigation.
EPSS PROB
3.3%
EPSS %ILE
88th
KEV
⚠ Exploited

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

A fix is referenced, but no release containing it is confirmed. Check the referenced fix and the vendor's advisory for a release that contains it and apply that within your standard update timelines at low or medium mission impact and sooner than that at high; until then, restrict network exposure of the affected system or apply the vendor's mitigation.

Exploitation active (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)14 days if the affected system is publicly exposed; 14 days if it is not.

In CISA KEV yes (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

CISA required action“Apply updates per vendor instructions.”

Quoted verbatim from CISA's Known Exploited Vulnerabilities catalog. CISA directs it at US federal civilian executive branch agencies under Binding Operational Directive (BOD) 26-04, which replaced BOD 22-01 on 10 June 2026; it is not EchelonGraph's advice. CISA's notes: https://nvd.nist.gov/vuln/detail/CVE-2009-2055

Published

August 19, 2009

Last Modified

April 22, 2026

Advisory Details (2)

Auto-updated May 20, 2026
⚠️ Actively exploited (CISA KEV). Fix referenced — no release confirmed yet. Sources: cisa.
CISA🔴 Active Exploitation

Known Exploited Vulnerabilities Catalog | CISA

Known Exploited Vulnerabilities Catalog | CISA. Listed in CISA Known Exploited Vulnerabilities catalog.

https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2009-2055
Web page
http://securitytracker.com/id?1022739

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 59× in last 7d / 244× 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 100 of 1,098 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. None are among the latest 100 rows. The 998 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-12 04:05 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  2. 2026-10-12 00:10 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  3. 2026-10-11 20:14 UTCEG score recompute
  4. 2026-10-11 20:14 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  5. 2026-10-11 16:20 UTCEG score recompute
  6. 2026-10-11 16:20 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  7. 2026-10-11 13:38 UTCEPSS rescoreEPSS 3.3% · 88th percentile
  8. 2026-10-11 12:27 UTCEG score recompute
  9. 2026-10-11 12:27 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  10. 2026-10-11 08:34 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  11. 2026-10-11 04:41 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  12. 2026-10-11 00:48 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  13. 2026-10-10 20:53 UTCEG score recompute
  14. 2026-10-10 20:53 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  15. 2026-10-10 19:54 UTCEPSS rescoreEPSS 3.3% · 88th percentile
  16. 2026-10-10 17:00 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  17. 2026-10-10 13:07 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  18. 2026-10-10 09:15 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  19. 2026-10-10 05:22 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  20. 2026-10-10 01:30 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  21. 2026-10-09 21:36 UTCEG score recompute
  22. 2026-10-09 21:36 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  23. 2026-10-09 20:00 UTCEPSS rescoreEPSS 3.3% · 88th percentile
  24. 2026-10-09 17:43 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  25. 2026-10-09 13:51 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
Show 75 more
  1. 2026-10-09 09:59 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  2. 2026-10-09 06:05 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  3. 2026-10-09 02:12 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  4. 2026-10-08 22:19 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  5. 2026-10-08 18:27 UTCEG score recompute
  6. 2026-10-08 18:27 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  7. 2026-10-08 16:33 UTCEPSS rescoreEPSS 3.3% · 88th percentile
  8. 2026-10-08 14:33 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  9. 2026-10-08 10:35 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  10. 2026-10-08 06:40 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  11. 2026-10-08 02:47 UTCEG score recompute
  12. 2026-10-08 02:47 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  13. 2026-10-07 23:37 UTCEPSS rescoreEPSS 3.3% · 88th percentile
  14. 2026-10-07 22:55 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  15. 2026-10-07 19:02 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  16. 2026-10-07 15:10 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  17. 2026-10-07 11:18 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  18. 2026-10-07 07:26 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  19. 2026-10-07 03:33 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  20. 2026-10-06 23:37 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  21. 2026-10-06 19:45 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  22. 2026-10-06 15:52 UTCEG score recompute
  23. 2026-10-06 15:52 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  24. 2026-10-06 15:09 UTCEPSS rescoreEPSS 3.3% · 88th percentile
  25. 2026-10-06 12:00 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  26. 2026-10-06 08:08 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  27. 2026-10-06 04:16 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  28. 2026-10-06 00:23 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  29. 2026-10-05 20:31 UTCEG score recompute
  30. 2026-10-05 20:30 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  31. 2026-10-05 17:37 UTCEPSS rescoreEPSS 3.3% · 88th percentile
  32. 2026-10-05 16:38 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  33. 2026-10-05 12:45 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  34. 2026-10-05 08:53 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  35. 2026-10-05 04:59 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  36. 2026-10-05 01:06 UTCEG score recompute
  37. 2026-10-05 01:06 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  38. 2026-10-04 23:15 UTCEPSS rescoreEPSS 3.3% · 88th percentile
  39. 2026-10-04 21:13 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  40. 2026-10-04 17:19 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  41. 2026-10-04 13:27 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  42. 2026-10-04 09:35 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  43. 2026-10-04 05:42 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  44. 2026-10-04 01:50 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  45. 2026-10-03 21:57 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  46. 2026-10-03 18:04 UTCEG score recompute
  47. 2026-10-03 18:04 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  48. 2026-10-03 14:08 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  49. 2026-10-03 10:16 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  50. 2026-10-03 06:24 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  51. 2026-10-03 02:32 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  52. 2026-10-02 22:39 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  53. 2026-10-02 18:48 UTCEG score recompute
  54. 2026-10-02 18:47 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  55. 2026-10-02 14:55 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  56. 2026-10-02 11:03 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  57. 2026-10-02 07:11 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  58. 2026-10-02 03:18 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  59. 2026-10-01 23:25 UTCEG score recompute
  60. 2026-10-01 23:25 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  61. 2026-10-01 19:30 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  62. 2026-10-01 15:38 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  63. 2026-10-01 11:46 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  64. 2026-10-01 07:51 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  65. 2026-10-01 03:59 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  66. 2026-10-01 00:07 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  67. 2026-09-30 20:14 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  68. 2026-09-30 16:22 UTCEG score recompute
  69. 2026-09-30 16:22 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  70. 2026-09-30 14:58 UTCEPSS rescoreEPSS 3.3% · 88th percentile
  71. 2026-09-30 12:29 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  72. 2026-09-30 08:35 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  73. 2026-09-30 04:42 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  74. 2026-09-30 00:48 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9
  75. 2026-09-29 20:55 UTCGHSA enrichmentGHSA-2j56-f322-jxrm · GitHub CVSS 5.9

Related CVEs(same CWE)

Frequently asked(6)

What is CVE-2009-2055?
CVE-2009-2055 is a critical-severity vulnerability; its CVE record was published on August 19, 2009. Cisco IOS XR 3.4.0 through 3.8.1 allows remote attackers to cause a denial of service (session reset) via a BGP UPDATE message with an invalid attribute, as demonstrated in the wild on 17 August 2009.
When was the CVE record for CVE-2009-2055 published?
The CVE record for CVE-2009-2055 was published on August 19, 2009. 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 April 22, 2026; the record at its source may have been updated since.
Is CVE-2009-2055 actively exploited?
Yes. CISA added CVE-2009-2055 to the Known Exploited Vulnerabilities catalog on March 25, 2022, affecting Cisco IOS XR. KEV listing indicates confirmed exploitation in the wild; this CVE warrants immediate attention. A fix is referenced, but no release containing it is confirmed. Check the referenced fix and the vendor's advisory for a release that contains it and apply that; until then, restrict network exposure of the affected system or apply the vendor's mitigation.
What is the CVSS score of CVE-2009-2055?
CVE-2009-2055 has a CVSS v3 base score of 5.9 (NVD). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 9.0 (CRITICAL).
Which products are affected by CVE-2009-2055?
CVE-2009-2055 affects Cisco IOS XR.
How do I remediate CVE-2009-2055?
A fix for CVE-2009-2055 is referenced (a reference tagged "Patch", often a source commit), but EchelonGraph has no release containing it on record. Check that reference and the vendor's advisory for a release that contains the fix and update to it; until then, restrict network exposure of the affected system or apply the vendor's mitigation.

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