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NVD / CVE Program· CNA mitre

CVE-2008-3656: Algorithmic complexity vulnerability in the WEBrick::HTTPUtils.split_header_value function in WEBrick::HTTP::DefaultFileHandler in WEBrick…

HighCVSS 7.8 · v2.0—Weaponized Fix available

Noroxi assessment

Priority: Plan (action score 52/100)

  • A ready-made attack module is public (Metasploit); exploiting it takes no special expertise.
  • Public proof-of-concept code exists (Exploit-DB); there is no record of exploitation in the wild.
  • Probability of exploitation in the next 30 days: 70.2% (FIRST EPSS); higher than 99.3% of all records.
  • No special conditions are required; it is repeatable.
  • Fixed version: ruby1.8 (Debian:4.0) 1.8.5-4etch3; ruby1.9 (Debian:4.0) 1.9.0+20060609-1etch3; irb (Red Hat:enterprise_linux:4::as) 0:1.8.1-7.el4_7.1.

Add it to your regular patch cycle. Upgrade to ruby1.8 (Debian:4.0) 1.8.5-4etch3; ruby1.9 (Debian:4.0) 1.9.0+20060609-1etch3; irb (Red Hat:enterprise_linux:4::as) 0:1.8.1-7.el4_7.1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

Algorithmic complexity vulnerability in the WEBrick::HTTPUtils.split_header_value function in WEBrick::HTTP::DefaultFileHandler in WEBrick in Ruby 1.8.5 and earlier, 1.8.6 through 1.8.6-p286, 1.8.7 through 1.8.7-p71, and 1.9 through r18423 allows context-dependent attackers to cause a denial of service (CPU consumption) via a crafted HTTP request that is processed by a backtracking regular expression.

Published
Aug 12, 2008
Updated
Jun 16, 2026
EPSS
70.2% · 99th percentile

Report tools

JSON

Action score

52

Plan

Add it to your regular patch cycle.

CVSS
31 / 40 · 7.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
21 / 30 · 70.2%

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  • Not in KEV: no record of exploitation in the wild
  • Weaponized exploit exists
  • A fix has been released

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  • when exploit code appears or is weaponized
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  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
ruby-langruby

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • ruby-lang rubyup to 1.8.5 inclusive
  • ruby-lang ruby1.6.8
  • ruby-lang ruby1.8.0
  • ruby-lang ruby1.8.1
  • ruby-lang ruby1.8.2
  • ruby-lang ruby1.8.3
  • ruby-lang ruby1.8.4
  • ruby-lang ruby1.8.5
+3 more rows
  • ruby-lang ruby1.8.6
  • ruby-lang ruby1.8.7
  • ruby-lang ruby1.9.0

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:4.0ruby1.8before 1.8.5-4etch31.8.5-4etch3
Debian:4.0ruby1.9before 1.9.0+20060609-1etch31.9.0+20060609-1etch3
Red Hat:enterprise_linux:4::asirbbefore 0:1.8.1-7.el4_7.10:1.8.1-7.el4_7.1
Red Hat:enterprise_linux:4::asrubybefore 0:1.8.1-7.el4_7.10:1.8.1-7.el4_7.1
Red Hat:enterprise_linux:4::asruby-debuginfobefore 0:1.8.1-7.el4_7.10:1.8.1-7.el4_7.1
Red Hat:enterprise_linux:4::asruby-develbefore 0:1.8.1-7.el4_7.10:1.8.1-7.el4_7.1
Red Hat:enterprise_linux:4::asruby-docsbefore 0:1.8.1-7.el4_7.10:1.8.1-7.el4_7.1
Red Hat:enterprise_linux:4::asruby-libsbefore 0:1.8.1-7.el4_7.10:1.8.1-7.el4_7.1
Red Hat:enterprise_linux:4::asruby-modebefore 0:1.8.1-7.el4_7.10:1.8.1-7.el4_7.1
Red Hat:enterprise_linux:4::asruby-tcltkbefore 0:1.8.1-7.el4_7.10:1.8.1-7.el4_7.1
Red Hat:enterprise_linux:5::clientruby-docsbefore 0:1.8.5-5.el5_2.50:1.8.5-5.el5_2.5
Red Hat:enterprise_linux:5::clientruby-irbbefore 0:1.8.5-5.el5_2.50:1.8.5-5.el5_2.5
Red Hat:enterprise_linux:5::clientruby-libsbefore 0:1.8.5-5.el5_2.50:1.8.5-5.el5_2.5
Red Hat:enterprise_linux:5::clientruby-rdocbefore 0:1.8.5-5.el5_2.50:1.8.5-5.el5_2.5
Red Hat:enterprise_linux:5::clientruby-ribefore 0:1.8.5-5.el5_2.50:1.8.5-5.el5_2.5
Red Hat:enterprise_linux:5::clientruby-tcltkbefore 0:1.8.5-5.el5_2.50:1.8.5-5.el5_2.5
Red Hat:enterprise_linux:5::client_workstationrubybefore 0:1.8.5-5.el5_2.50:1.8.5-5.el5_2.5
Red Hat:enterprise_linux:5::client_workstationruby-debuginfobefore 0:1.8.5-5.el5_2.50:1.8.5-5.el5_2.5
Red Hat:enterprise_linux:5::client_workstationruby-develbefore 0:1.8.5-5.el5_2.50:1.8.5-5.el5_2.5
Red Hat:enterprise_linux:5::client_workstationruby-modebefore 0:1.8.5-5.el5_2.50:1.8.5-5.el5_2.5
Red Hat:hummingbird:1ruby3.3before 0:3.3.10-23.1.hum10:3.3.10-23.1.hum1
Red Hat:hummingbird:1ruby3.3-bundled-gemsbefore 0:3.3.10-23.1.hum10:3.3.10-23.1.hum1
Red Hat:hummingbird:1ruby3.3-default-gemsbefore 0:3.3.10-23.1.hum10:3.3.10-23.1.hum1
Red Hat:hummingbird:1ruby3.3-develbefore 0:3.3.10-23.1.hum10:3.3.10-23.1.hum1

+14

Same product

ruby-lang: all records

Other highest-scoring records for the same primary product.

  • CVE-2017-17405Ruby before 2.4.3 allows Net::FTP command injection.
    57Plan
  • CVE-2021-28966In Ruby through 3.0 on Windows, a remote attacker can submit a crafted path when a Web application handles a parameter with TmpDir.
    47Plan
  • CVE-2017-14064Ruby through 2.2.7, 2.3.x through 2.3.4, and 2.4.x through 2.4.1 can expose arbitrary memory during a JSON.generate call.
    42Plan

Published before and after this one in the same product

  • ← EarlierCVE-2008-2726Jun 24, 2008 · Integer overflow in the (1) rb_ary_splice function in Ruby 1.8.4 and earlier, 1.8.5 before 1.8.5-p231, 1.8.6 before 1.8.6-p230, 1.8.7…
    32Monitor
  • ← EarlierCVE-2008-3655Aug 12, 2008 · Ruby 1.8.5 and earlier, 1.8.6 through 1.8.6-p286, 1.8.7 through 1.8.7-p71, and 1.9 through r18423 does not properly restrict access to…
    34Monitor
  • Later →CVE-2008-3657Aug 12, 2008 · The dl module in Ruby 1.8.5 and earlier, 1.8.6 through 1.8.6-p286, 1.8.7 through 1.8.7-p71, and 1.9 through r18423 does not check…
    34Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
debian:ruby1.81.8.5-4etch3 · Debian:4.0Package registry (OSV)
debian:ruby1.91.9.0+20060609-1etch3 · Debian:4.0Package registry (OSV)
red hat:irb0:1.8.1-7.el4_7.1 · Red Hat:enterprise_linux:4::asPackage registry (OSV)
red hat:ruby0:1.8.1-7.el4_7.1 · Red Hat:enterprise_linux:4::asPackage registry (OSV)
red hat:ruby-debuginfo0:1.8.1-7.el4_7.1 · Red Hat:enterprise_linux:4::asPackage registry (OSV)
red hat:ruby-devel0:1.8.1-7.el4_7.1 · Red Hat:enterprise_linux:4::asPackage registry (OSV)
red hat:ruby-docs0:1.8.1-7.el4_7.1 · Red Hat:enterprise_linux:4::asPackage registry (OSV)
red hat:ruby-irb0:1.8.5-5.el5_2.5 · Red Hat:enterprise_linux:5::clientPackage registry (OSV)
red hat:ruby-libs0:1.8.1-7.el4_7.1 · Red Hat:enterprise_linux:4::asPackage registry (OSV)
red hat:ruby-mode0:1.8.1-7.el4_7.1 · Red Hat:enterprise_linux:4::asPackage registry (OSV)
red hat:ruby-rdoc0:1.8.5-5.el5_2.5 · Red Hat:enterprise_linux:5::clientPackage registry (OSV)
red hat:ruby-ri0:1.8.5-5.el5_2.5 · Red Hat:enterprise_linux:5::clientPackage registry (OSV)
red hat:ruby-tcltk0:1.8.1-7.el4_7.1 · Red Hat:enterprise_linux:4::asPackage registry (OSV)
red hat:ruby3.30:3.3.10-23.1.hum1 · Red Hat:hummingbird:1Package registry (OSV)

Exploit status

Weaponized

A ready exploit tool or active in-the-wild use is known for this vulnerability. This should be your top priority.

Evidence

  • Metasploit module ×1
  • Exploit-DB entry ×1

Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.

Public exploit evidence
SourceKindDate
Exploit-DB entrydos2008-08-11
Metasploit moduleauxiliary/dos/http/webrick_regexRuby WEBrick::HTTP::DefaultFileHandler DoSauxiliary2008-08-08

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

  1. Metasploit-5 d
  2. First PoC-2 d
  3. Published
  4. TodayNov 14, 2026+6667 d

Bug bounty scope

The product’s vendor appears in a public program. Matched by name; verify the scope text in the program.

Not on record for this CVE: EPSS history · patch commit or PR link · researcher credit · variant or chain candidate.

Technical details

Attack conditions

  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
C · the service can be disrupted
Attack complexity
Low
Confidentiality impact
None
Integrity impact
None
Availability impact
C

Weakness class (CWE)

CWE-399 · Resource Management Errors

CVSS vector

AV:N/AC:L/Au:N/C:N/I:N/A:C

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

References

Show all references (19 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records