squid: DoS (100% CPU use) while processing certain external ACL helper HTTP headers
Published Aug 18, 2009
5.0
MEDIUMCVSS 2.0
EPSS 34.03%
Description
The strListGetItem function in src/HttpHeaderTools.c in Squid 2.7 allows remote attackers to cause a denial of service via a crafted auth header with certain comma delimiters that trigger an infinite loop of calls to the strcspn function.
Affected products
No data.
- 2.7
- 2.7
- 2.7
No data.
Red Hat Enterprise Linux 5
squid-7:2.6.STABLE21-6.el5
Fixed · RHSA-2010:0221
| Product | Package | State | Advisory |
|---|---|---|---|
| Red Hat Enterprise Linux 5 | squid-7:2.6.STABLE21-6.el5 | Fixed | RHSA-2010:0221 |
No package ranges for this CVE.
Remediation
Red Hat statement
This issue did not affect the versions of the squid packages, as shipped with Red Hat Enterprise Linux 3 and 4.
Metrics
No CVSS v4.0 score for this CVE.
No CVSS v3.1 score for this CVE.
No CVSS v3.0 score for this CVE.
AV:N/AC:L/Au:N/C:N/I:N/A:P
This CVE is not in the KEV list.
No CISA SSVC assessment for this CVE yet.
Estimated probability of exploitation in the wild in the next 30 days (FIRST EPSS). As of Oct 1, 2026.
Score over time
2022–2026- EPSS v2
- EPSS v3
- EPSS v4
- EPSS v5
Percentile over time
- EPSS v2
- EPSS v3
- EPSS v4
- EPSS v5
Table of values (13 key points)
Flat stretches are collapsed; showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 1, 2026 | 34.03% (0.34031) | 98.36th | v5 (v2026.06.15) |
| Sep 8, 2026 | 34.03% (0.34031) | 98.29th | v5 (v2026.06.15) |
| Jun 15, 2026 | 36.73% (0.36732) | 98.30th | v5 (v2026.06.15) |
| May 6, 2025 | 60.66% (0.60658) | 98.16th | v4 (v2025.03.14) |
| Mar 30, 2025 | 68.71% (0.68709) | 98.51th | v4 (v2025.03.14) |
| Mar 29, 2025 | 67.52% (0.67520) | 98.03th | v4 (v2025.03.14) |
| Mar 19, 2025 | 68.71% (0.68709) | 98.49th | v4 (v2025.03.14) |
| Mar 17, 2025 | 66.71% (0.66711) | 98.41th | v4 (v2025.03.14) |
| Dec 12, 2024 | 96.50% (0.96495) | 99.66th | v3 (v2023.03.01) |
| Mar 7, 2023 | 96.50% (0.96495) | 99.26th | v3 (v2023.03.01) |
| Mar 6, 2023 | 2.17% (0.02172) | 80.77th | v2 (v2022.01.01) |
| Apr 1, 2022 | 2.17% (0.02172) | 78.91th | v2 (v2022.01.01) |
| Feb 4, 2022 | 2.17% (0.02172) | 57.73th | v2 (v2022.01.01) |
References (15)
- http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=534982 x_refsource_CONFIRM
- http://bugs.debian.org/cgi-bin/bugreport.cgi?msg=31%3Bfilename=diff%3Batt=1%3Bbug=534982 x_refsource_MISC
- http://www.openwall.com/lists/oss-security/2009/07/20/10 mailing-listx_refsource_MLIST
- http://www.openwall.com/lists/oss-security/2009/08/03/3 mailing-listx_refsource_MLIST
- http://www.openwall.com/lists/oss-security/2009/08/04/6 mailing-listx_refsource_MLIST
- http://www.securityfocus.com/bid/36091 vdb-entryx_refsource_BID
- http://www.securitytracker.com/id?1022757 vdb-entryx_refsource_SECTRACK
- http://www.squid-cache.org/bugs/show_bug.cgi?id=2541 x_refsource_CONFIRM
- http://www.squid-cache.org/bugs/show_bug.cgi?id=2704 x_refsource_MISCVendor Advisory
- https://access.redhat.com/security/cve/CVE-2009-2855 Vendor Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=518182 x_refsource_CONFIRMIssue Tracking
- https://exchange.xforce.ibmcloud.com/vulnerabilities/52610 vdb-entryx_refsource_XF
- https://nvd.nist.gov/vuln/detail/CVE-2009-2855
- https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A10592 vdb-entrysignaturex_refsource_OVAL
- https://www.cve.org/CVERecord?id=CVE-2009-2855
Change history (0)
No recorded changes yet.