squid: Invalid free by processing CNAME DNS record pointing to another CNAME record pointing to an empty A-record
Published Nov 17, 2011
5.0
MEDIUMCVSS 2.0
EPSS 37.19%
Description
The idnsGrokReply function in Squid before 3.1.16 does not properly free memory, which allows remote attackers to cause a denial of service (daemon abort) via a DNS reply containing a CNAME record that references another CNAME record that contains an empty A record.
Affected products
No data.
- ≤ 3.1.15
- 3.0
- 3.0
- 3.0
- 3.0
- 3.0
- 3.0
- 3.0
- 3.0
- 3.0
- 3.0
- 3.0
- 3.0
- 3.0
- 3.0
- 3.0
- 3.0
- 3.0
- 3.0
- 3.0
- 3.0
- 3.0
- 3.0
- 3.0
- 3.0
- 3.0
- 3.0.stable1
- 3.0.stable2
- 3.0.stable3
- 3.0.stable4
- 3.0.stable5
- 3.0.stable6
- 3.0.stable7
- 3.0.stable8
- 3.0.stable9
- 3.0.stable10
- 3.0.stable11
- 3.0.stable11
- 3.0.stable12
- 3.0.stable13
- 3.0.stable14
- 3.0.stable15
- 3.0.stable16
- 3.0.stable16
- 3.0.stable17
- 3.0.stable18
- 3.0.stable19
- 3.0.stable20
- 3.0.stable21
- 3.0.stable22
- 3.0.stable23
- 3.0.stable24
- 3.0.stable25
- 3.1
- 3.1.0.1
- 3.1.0.2
- 3.1.0.3
- 3.1.0.4
- 3.1.0.5
- 3.1.0.6
- 3.1.0.7
- 3.1.0.8
- 3.1.0.9
- 3.1.0.10
- 3.1.0.11
- 3.1.0.12
- 3.1.0.13
- 3.1.0.14
- 3.1.0.15
- 3.1.0.16
- 3.1.0.17
- 3.1.0.18
- 3.1.1
- 3.1.2
- 3.1.3
- 3.1.4
- 3.1.5
- 3.1.5.1
- 3.1.6
- 3.1.7
- 3.1.8
- 3.1.9
- 3.1.10
- 3.1.11
- 3.1.12
- 3.1.13
- 3.1.14
No data.
Red Hat Enterprise Linux 6
squid-7:3.1.10-1.el6_2.1
Fixed · RHSA-2011:1791
Red Hat Enterprise Linux 4
squid
Not affected
Red Hat Enterprise Linux 5
squid
Not affected
| Product | Package | State | Advisory |
|---|---|---|---|
| Red Hat Enterprise Linux 6 | squid-7:3.1.10-1.el6_2.1 | Fixed | RHSA-2011:1791 |
| Red Hat Enterprise Linux 4 | squid | Not affected | n/a |
| Red Hat Enterprise Linux 5 | squid | Not affected | n/a |
No package ranges for this CVE.
Remediation
Red Hat statement
This issue did not affect the versions of squid as shipped with Red Hat Enterprise Linux 4 and 5 as they did not include IPv6 support. This issue was introduced with the addition of IPv6 support in Squid 3.1 (in the changes made to the idnsGrokReply function).
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 (20 key points)
Flat stretches are collapsed; showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 1, 2026 | 37.19% (0.37186) | 98.48th | v5 (v2026.06.15) |
| Jul 2, 2026 | 37.19% (0.37186) | 98.33th | v5 (v2026.06.15) |
| Jun 15, 2026 | 38.32% (0.38321) | 98.38th | v5 (v2026.06.15) |
| Dec 28, 2025 | 62.49% (0.62490) | 98.28th | v4 (v2025.03.14) |
| Dec 27, 2025 | 64.04% (0.64043) | 98.37th | v4 (v2025.03.14) |
| Oct 28, 2025 | 62.49% (0.62490) | 98.27th | v4 (v2025.03.14) |
| Oct 27, 2025 | 64.04% (0.64043) | 98.35th | v4 (v2025.03.14) |
| Oct 1, 2025 | 62.49% (0.62490) | 98.32th | v4 (v2025.03.14) |
| Jul 30, 2025 | 64.04% (0.64043) | 98.34th | v4 (v2025.03.14) |
| Jun 3, 2025 | 62.49% (0.62490) | 98.26th | v4 (v2025.03.14) |
| Mar 30, 2025 | 60.16% (0.60164) | 98.10th | v4 (v2025.03.14) |
| Mar 29, 2025 | 63.73% (0.63731) | 97.78th | v4 (v2025.03.14) |
| Mar 17, 2025 | 60.16% (0.60164) | 98.07th | v4 (v2025.03.14) |
| Dec 12, 2024 | 93.46% (0.93458) | 99.20th | v3 (v2023.03.01) |
| Mar 7, 2023 | 93.46% (0.93458) | 98.50th | v3 (v2023.03.01) |
| Mar 6, 2023 | 2.17% (0.02172) | 80.77th | v2 (v2022.01.01) |
| Feb 13, 2023 | 2.17% (0.02172) | 80.28th | v2 (v2022.01.01) |
| Feb 3, 2023 | 3.78% (0.03779) | 85.12th | 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.squid-cache.org/show_bug.cgi?id=3237#c12 x_refsource_MISC
- http://lists.opensuse.org/opensuse-security-announce/2016-08/msg00010.html vendor-advisoryx_refsource_SUSE
- http://lists.opensuse.org/opensuse-security-announce/2016-08/msg00040.html vendor-advisoryx_refsource_SUSE
- http://secunia.com/advisories/46609 third-party-advisoryx_refsource_SECUNIAVendor Advisory
- http://secunia.com/advisories/47459 third-party-advisoryx_refsource_SECUNIA
- http://www.mandriva.com/security/advisories?name=MDVSA-2011:193 vendor-advisoryx_refsource_MANDRIVA
- http://www.openwall.com/lists/oss-security/2011/10/31/5 mailing-listx_refsource_MLIST
- http://www.openwall.com/lists/oss-security/2011/11/01/3 mailing-listx_refsource_MLIST
- http://www.redhat.com/support/errata/RHSA-2011-1791.html vendor-advisoryx_refsource_REDHAT
- http://www.securitytracker.com/id?1026265 vdb-entryx_refsource_SECTRACK
- http://www.squid-cache.org/Versions/v3/3.1/changesets/SQUID_3_1_16.html x_refsource_CONFIRM
- https://access.redhat.com/security/cve/CVE-2011-4096 Vendor Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=750316 Issue Tracking
- https://nvd.nist.gov/vuln/detail/CVE-2011-4096
- https://www.cve.org/CVERecord?id=CVE-2011-4096
Change history (0)
No recorded changes yet.