CVE-2009-1955

HIGHNVD 7.57.5—
EchelonGraph scoreMEDIUM confidence

Score 7.5 from GitHub Security Advisory published 2022-05-02. NVD baseline CVSS 7.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
Weaponized
7.5
EchelonGraph verdictPatch this weekExploitation is likely or a public exploit exists.
  • 609 internet-exposed hosts are running an affected version right now
  • High exploitation likelihood — EPSS 53%
CISA-KEV: Not listedEPSS: 53%CVSS: 7.5Exploit: NoneExposed: 609

A fix is available — apply it.

The expat XML parser in the apr_xml_* interface in xml/apr_xml.c in Apache APR-util before 1.3.7, as used in the mod_dav and mod_dav_svn modules in the Apache HTTP Server, allows remote attackers to cause a denial of service (memory consumption) via a crafted XML document containing a large number of nested entity references, as demonstrated by a PROPFIND request, a similar issue to CVE-2003-1564.

Live · internet exposure

609 internet-exposed hosts are running an affected version of CVE-2009-1955 right now.

across 61 countries (United States, Germany, Japan, France, Netherlands)top: http_server
See the live KEV-Exposure radar →Found passively from public internet-scan data — aggregate, host-redacted.

EchelonGraph is the only CVE feed that fuses live vulnerability intelligence with its own live internet-exposure radar — so you see not just that a CVE is exploited, but how much of the internet is exposed to it right now.

CVSS v3
7.5
EG Score
7.5(medium)
EPSS
98.8%
KEV
Not listed

Published

June 8, 2009

Last Modified

April 23, 2026

Advisory Details (8)

Auto-updated May 30, 2026
No patch confirmed yet.
generic

About Secunia Research | Flexera

http://secunia.com/advisories/35487
generic

About Secunia Research | Flexera

http://secunia.com/advisories/35444
generic

About Secunia Research | Flexera

http://secunia.com/advisories/35395
generic

About Secunia Research | Flexera

http://secunia.com/advisories/35360
generic

About Secunia Research | Flexera

http://secunia.com/advisories/35284
generic

About Secunia Research | Flexera

http://secunia.com/advisories/34724
generic

'[security bulletin] HPSBUX02612 SSRT100345 rev.1 - HP-UX Apache-based Web Server, Local Information' - MARC

http://marc.info/?l=bugtraq&m=129190899612998&w=2
generic

'[PATCH] prevent "billion laughs" attack against expat' - MARC

http://marc.info/?l=apr-dev&m=124396021826125&w=2

Vendor Advisories for CVE-2009-1955(1)

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

Patch Availability(6)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntulibaprutil1 (1.2.12+dfsg-7ubuntu0.1) @ intrepid2026-05-30ubuntu
ubuntuapache2-mpm-prefork (2.2.11-2ubuntu2.1) @ jaunty2026-05-30ubuntu
redhatxml-commons-0:1.3.02-2jpp_1rh2010-08-04redhat
redhathttpd22-0:2.2.10-23.1.ep5.el42009-07-17redhat
redhathttpd-0:2.0.46-73.ent2009-06-16redhat
redhatapr-util-0:1.2.7-7.el5_3.12009-06-16redhat

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.

Weakness Classification(1)

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

Additional Vendor Advisories

(5)

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 4× in last 7d / 32× 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.

  1. 2026-07-07 18:11 UTCOSV refresh
  2. 2026-07-06 02:19 UTCEPSS rescore
  3. 2026-07-06 02:19 UTCEPSS rescore
  4. 2026-07-01 15:02 UTCEPSS rescore
  5. 2026-06-30 23:19 UTCEPSS rescore
  6. 2026-06-28 04:52 UTCEPSS rescore
  7. 2026-06-28 04:52 UTCEPSS rescore
  8. 2026-06-27 03:05 UTCEPSS rescore
  9. 2026-06-25 13:46 UTCEPSS rescore
  10. 2026-06-25 13:46 UTCEPSS rescore
  11. 2026-06-24 14:02 UTCEPSS rescore
  12. 2026-06-24 14:02 UTCEPSS rescore
  13. 2026-06-23 21:29 UTCEPSS rescore
  14. 2026-06-23 21:29 UTCEPSS rescore
  15. 2026-06-21 01:56 UTCEPSS rescore
  16. 2026-06-21 01:56 UTCEPSS rescore
  17. 2026-06-19 05:25 UTCOSV refresh
  18. 2026-06-18 17:49 UTCEPSS rescore
  19. 2026-06-18 17:49 UTCEPSS rescore
  20. 2026-06-17 17:49 UTCEPSS rescore
  21. 2026-06-17 17:49 UTCEPSS rescore
  22. 2026-06-16 17:49 UTCEPSS rescore
  23. 2026-06-16 17:49 UTCEPSS rescore
  24. 2026-06-15 17:44 UTCEPSS rescore
  25. 2026-06-14 23:14 UTCEPSS rescore
Show 47 more
  1. 2026-06-14 23:14 UTCEPSS rescore
  2. 2026-06-13 22:57 UTCEPSS rescore
  3. 2026-06-12 23:08 UTCEPSS rescore
  4. 2026-06-12 23:08 UTCEPSS rescore
  5. 2026-06-10 22:14 UTCEPSS rescore
  6. 2026-06-10 13:17 UTCEPSS rescore
  7. 2026-06-08 14:13 UTCEPSS rescore
  8. 2026-06-07 15:22 UTCEPSS rescore
  9. 2026-06-07 15:22 UTCEPSS rescore
  10. 2026-06-06 13:44 UTCEPSS rescore
  11. 2026-06-06 13:44 UTCEPSS rescore
  12. 2026-06-06 13:44 UTCEPSS rescore
  13. 2026-06-05 22:44 UTCEPSS rescore
  14. 2026-06-05 22:44 UTCEPSS rescore
  15. 2026-06-05 06:07 UTCEPSS rescore
  16. 2026-06-04 13:09 UTCEPSS rescore
  17. 2026-06-04 13:09 UTCEPSS rescore
  18. 2026-06-02 20:10 UTCEPSS rescore
  19. 2026-06-02 20:10 UTCEPSS rescore
  20. 2026-06-01 13:49 UTCEPSS rescore
  21. 2026-06-01 13:49 UTCEPSS rescore
  22. 2026-05-31 22:28 UTCEPSS rescore
  23. 2026-05-31 22:28 UTCEPSS rescore
  24. 2026-05-31 00:13 UTCEPSS rescore
  25. 2026-05-31 00:13 UTCEPSS rescore
  26. 2026-05-30 16:37 UTCEG score recompute
  27. 2026-05-30 16:37 UTCVendor advisory
  28. 2026-05-30 16:37 UTCGHSA enrichment
  29. 2026-05-29 13:40 UTCEPSS rescore
  30. 2026-05-28 13:42 UTCEPSS rescore
  31. 2026-05-28 13:42 UTCEPSS rescore
  32. 2026-05-28 13:42 UTCEPSS rescore
  33. 2026-05-27 13:38 UTCEPSS rescore
  34. 2026-05-27 13:38 UTCEPSS rescore
  35. 2026-05-26 13:41 UTCEPSS rescore
  36. 2026-05-26 13:41 UTCEPSS rescore
  37. 2026-05-26 07:16 UTCEPSS rescore
  38. 2026-05-26 07:16 UTCEPSS rescore
  39. 2026-05-24 16:43 UTCEPSS rescore
  40. 2026-05-22 21:15 UTCEPSS rescore
  41. 2026-05-22 21:15 UTCEPSS rescore
  42. 2026-05-22 10:56 UTCOSV refresh
  43. 2026-05-20 22:37 UTCEPSS rescore
  44. 2026-05-20 22:37 UTCEPSS rescore
  45. 2026-05-20 11:21 UTCEPSS rescore
  46. 2026-05-20 11:20 UTCEPSS rescore
  47. 2026-05-18 21:29 UTCEPSS rescore

Publicly available exploits

(1 reference)

Working exploit code is in the public domain (1 Exploit-DB entry). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • Exploit-DBEDB-8842✓ verified
    First seen Jun 1, 2009

    Apache mod_dav / svn - Remote Denial of Service

    Open source ↗

Frequently asked(5)

What is CVE-2009-1955?
CVE-2009-1955 is a high vulnerability published on June 8, 2009. The expat XML parser in the aprxml* interface in xml/aprxml.c in Apache APR-util before 1.3.7, as used in the moddav and moddavsvn modules in the Apache HTTP Server, allows remote attackers to cause a denial of service (memory consumption) via a crafted XML document containing a large number of…
When was CVE-2009-1955 disclosed?
CVE-2009-1955 was first published in the National Vulnerability Database on June 8, 2009, with the most recent update on April 23, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2009-1955 actively exploited?
CVE-2009-1955 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 98.8% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2009-1955?
CVE-2009-1955 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2009-1955?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2009-1955, 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

Explore the affected products and dependency analysis for CVE-2009-1955

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