CVE-2009-1955

HIGHNVD 7.58.1▲
EchelonGraph scoreHIGH confidence

Score elevated to 8.1 because EPSS predicts 53% probability of exploitation within the next 30 days (98th percentile of EPSS-scored CVEs). NVD baseline CVSS 7.5 retained for reference. Confidence: see factors.

Triggered by: EPSS exploit prediction (continuous uplift above 30%)
Sources: epss, ghsa, nvd
Weaponized
8.1EG
EchelonGraph verdictPatch this weekExploitation is likely or a public exploit exists.
  • 2,682 internet-facing services (distinct ip:port) on record running an affected version — derived from Shodan data (© Shodan); a patched service can stay counted while its port stays open
  • High exploitation likelihood — EPSS 53%
  • Public exploit code is available (Exploit-DB (verified), epss top5pct, epss high, public exploit)
CISA-KEV: Not listedEPSS PROB: 53%CVSS: 7.5Exploit: Exploit-DB (verified) · epss top5pct · epss high · public exploitExposed services: 2,682

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.

Internet exposure · derived from Shodan data

2,682 internet-facing services (distinct ip:port) on record running a version that maps to CVE-2009-1955, in our KEV-Exposure radar’s Shodan-derived sample.

across 95 countries (United States, Germany, Japan, France, Netherlands)top: http_server
See the KEV-Exposure radar →Derived from Shodan data. Shodan data is owned by Shodan, which holds its copyright (© Shodan). EchelonGraph claims no ownership of it or copyright in it. Aggregate, host-redacted.

How it counts: every 12 hours, when Shodan query credits allow, the radar runs one Shodan query per tracked product, reads up to 100 ip:port services per query, and keeps a service when its banner version matches a CISA-KEV or high-EPSS CVE; a service is dropped when neither a search nor a Shodan InternetDB port re-check has refreshed it for 21 days. A re-check that finds the port still listed by Shodan InternetDB refreshes the service without re-reading the banner, so a patched service can stay counted while its port stays open. A count is a banner-version inference over a sample, not an exploit test and not an internet-wide census, and the unit is a service, not a machine: a machine answering on two ports counts twice.

CVSS v3
7.5
EG Score
8.1HIGHhigh confidence
EG Risk
67
EG Risk 67/100CISA SSVC

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
Severity81% × 45%
Exploitation65% × 40%
Automatability30% × 15%
CISA SSVC: Track at low or medium mission impact; Track* or Attend at high (mission-essential systems).
Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
EPSS PROB
53%
EPSS %ILE
98th
KEV
Not listed

CISA SSVCTrack at low or medium mission impact; Track* or Attend at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation public PoC (EG-KEV: weaponized) · Automatable unknown (not published for this CVE) · Technical impact partial (CVSS below 9.0). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

June 8, 2009

Last Modified

April 23, 2026

Advisory Details (8)

Auto-updated May 30, 2026
Patch available.
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 / EcosystemFix (by version range) / 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.

Affected Packages

(6 across 6 ecosystems)
Debian:11(1)
PackageVulnerable rangeFix by version rangeDependents
apr-util—
  • every version up to 1.3.7+dfsg-1: fixed in 1.3.7+dfsg-1
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
apr-util—
  • every version up to 1.3.7+dfsg-1: fixed in 1.3.7+dfsg-1
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
apr-util—
  • every version up to 1.3.7+dfsg-1: fixed in 1.3.7+dfsg-1
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
apr-util—
  • every version up to 1.3.7+dfsg-1: fixed in 1.3.7+dfsg-1
—
Debian:4.0(1)
PackageVulnerable rangeFix by version rangeDependents
apr-util1.2.7+dfsg-2
  • every version up to 1.2.7+dfsg-2+etch2: fixed in 1.2.7+dfsg-2+etch2
—
Debian:5.0(1)
PackageVulnerable rangeFix by version rangeDependents
apr-util1.2.12+dfsg-8
  • every version up to 1.2.12+dfsg-8+lenny2: fixed in 1.2.12+dfsg-8+lenny2
—

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 / 14× 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 120 total refreshes for this CVE.

  1. 2026-10-09 20:00 UTCEPSS rescore
  2. 2026-10-07 23:37 UTCEPSS rescore
  3. 2026-10-06 15:09 UTCEPSS rescore
  4. 2026-10-03 09:39 UTCOSV refresh
  5. 2026-09-30 14:58 UTCEPSS rescore
  6. 2026-09-29 07:58 UTCEG score recompute
  7. 2026-09-27 13:39 UTCEPSS rescore
  8. 2026-09-26 15:52 UTCEPSS rescore
  9. 2026-09-24 13:57 UTCEPSS rescore
  10. 2026-09-17 19:20 UTCEPSS rescore
  11. 2026-09-15 03:04 UTCEPSS rescore
  12. 2026-09-14 04:20 UTCOSV refresh
  13. 2026-09-12 14:54 UTCEPSS rescore
  14. 2026-09-10 09:24 UTCEPSS rescore
  15. 2026-09-06 13:41 UTCEPSS rescore
  16. 2026-09-05 15:22 UTCEPSS rescore
  17. 2026-09-04 13:55 UTCEPSS rescore
  18. 2026-08-28 21:34 UTCEPSS rescore
  19. 2026-08-26 05:41 UTCOSV refresh
  20. 2026-08-25 13:43 UTCEPSS rescore
  21. 2026-08-19 16:58 UTCEPSS rescore
  22. 2026-08-15 01:24 UTCEPSS rescore
  23. 2026-08-09 22:10 UTCOSV refresh
  24. 2026-08-08 16:31 UTCEPSS rescore
  25. 2026-08-06 13:41 UTCEPSS rescore
Show 75 more
  1. 2026-07-30 16:22 UTCEPSS rescore
  2. 2026-07-30 01:26 UTCEPSS rescore
  3. 2026-07-25 14:12 UTCEPSS rescore
  4. 2026-07-24 22:41 UTCOSV refresh
  5. 2026-07-24 14:12 UTCEPSS rescore
  6. 2026-07-23 14:14 UTCEPSS rescore
  7. 2026-07-23 00:59 UTCEG score recompute
  8. 2026-07-23 00:37 UTCEG score recompute
  9. 2026-07-23 00:04 UTCEG score recompute▲ 0.60
  10. 2026-07-22 21:42 UTCEG score recompute
  11. 2026-07-22 14:03 UTCEPSS rescore
  12. 2026-07-21 15:20 UTCEPSS rescore
  13. 2026-07-20 17:03 UTCEPSS rescore
  14. 2026-07-20 17:03 UTCEPSS rescore
  15. 2026-07-16 16:58 UTCEPSS rescore
  16. 2026-07-15 16:54 UTCEPSS rescore
  17. 2026-07-15 16:54 UTCEPSS rescore
  18. 2026-07-15 01:55 UTCEPSS rescore
  19. 2026-07-13 06:07 UTCEPSS rescore
  20. 2026-07-11 08:22 UTCEPSS rescore
  21. 2026-07-11 08:22 UTCEPSS rescore
  22. 2026-07-09 19:04 UTCEPSS rescore
  23. 2026-07-08 15:10 UTCEPSS rescore
  24. 2026-07-07 18:11 UTCOSV refresh
  25. 2026-07-06 02:19 UTCEPSS rescore
  26. 2026-07-06 02:19 UTCEPSS rescore
  27. 2026-07-01 15:02 UTCEPSS rescore
  28. 2026-06-30 23:19 UTCEPSS rescore
  29. 2026-06-28 04:52 UTCEPSS rescore
  30. 2026-06-28 04:52 UTCEPSS rescore
  31. 2026-06-27 03:05 UTCEPSS rescore
  32. 2026-06-25 13:46 UTCEPSS rescore
  33. 2026-06-25 13:46 UTCEPSS rescore
  34. 2026-06-24 14:02 UTCEPSS rescore
  35. 2026-06-24 14:02 UTCEPSS rescore
  36. 2026-06-23 21:29 UTCEPSS rescore
  37. 2026-06-23 21:29 UTCEPSS rescore
  38. 2026-06-21 01:56 UTCEPSS rescore
  39. 2026-06-21 01:56 UTCEPSS rescore
  40. 2026-06-19 05:25 UTCOSV refresh
  41. 2026-06-18 17:49 UTCEPSS rescore
  42. 2026-06-18 17:49 UTCEPSS rescore
  43. 2026-06-17 17:49 UTCEPSS rescore
  44. 2026-06-17 17:49 UTCEPSS rescore
  45. 2026-06-16 17:49 UTCEPSS rescore
  46. 2026-06-16 17:49 UTCEPSS rescore
  47. 2026-06-15 17:44 UTCEPSS rescore
  48. 2026-06-14 23:14 UTCEPSS rescore
  49. 2026-06-14 23:14 UTCEPSS rescore
  50. 2026-06-13 22:57 UTCEPSS rescore
  51. 2026-06-12 23:08 UTCEPSS rescore
  52. 2026-06-12 23:08 UTCEPSS rescore
  53. 2026-06-10 22:14 UTCEPSS rescore
  54. 2026-06-10 13:17 UTCEPSS rescore
  55. 2026-06-08 14:13 UTCEPSS rescore
  56. 2026-06-07 15:22 UTCEPSS rescore
  57. 2026-06-07 15:22 UTCEPSS rescore
  58. 2026-06-06 13:44 UTCEPSS rescore
  59. 2026-06-06 13:44 UTCEPSS rescore
  60. 2026-06-06 13:44 UTCEPSS rescore
  61. 2026-06-05 22:44 UTCEPSS rescore
  62. 2026-06-05 22:44 UTCEPSS rescore
  63. 2026-06-05 06:07 UTCEPSS rescore
  64. 2026-06-04 13:09 UTCEPSS rescore
  65. 2026-06-04 13:09 UTCEPSS rescore
  66. 2026-06-02 20:10 UTCEPSS rescore
  67. 2026-06-02 20:10 UTCEPSS rescore
  68. 2026-06-01 13:49 UTCEPSS rescore
  69. 2026-06-01 13:49 UTCEPSS rescore
  70. 2026-05-31 22:28 UTCEPSS rescore
  71. 2026-05-31 22:28 UTCEPSS rescore
  72. 2026-05-31 00:13 UTCEPSS rescore
  73. 2026-05-31 00:13 UTCEPSS rescore
  74. 2026-05-30 16:37 UTCEG score recompute
  75. 2026-05-30 16:37 UTCVendor advisory

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 ↗

Related CVEs(same product + same vendor + same CWE)

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 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. EchelonGraph's EG-KEV model classifies it as weaponized: a functional public exploit exists. FIRST EPSS estimates a 53% probability of exploitation in the next 30 days (98th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2009-1955?
CVE-2009-1955 has a CVSS v3 base score of 7.5 (NVD). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 8.1 (HIGH).
How do I remediate CVE-2009-1955?
A fix for CVE-2009-1955 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2009-1955 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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