CVE-2011-1473

OpenSSL before 0.9.8l, and 0.9.8m through 1.x, does not properly restrict client-initiated renegotiation within the SSL and TLS protocols, which might make it easier for remote attackers to cause a denial of service (CPU consumption) by performing many renegotiations within a single connection, a different vulnerability than CVE-2011-5094. NOTE: it can also be argued that it is the responsibility of server deployments, not a security library, to prevent or limit renegotiation when it is inappropriate within a specific environment

Published: 2012-06-16 Last update: 2026-04-29 Assigner: [email protected] Source: [email protected]

Conclusion & alert: CVE-2011-1473 is rated Moderate Risk (59.7/100): CVSS Medium severity, with high exploitation likelihood (EPSS 67.70%, 99th percentile). Core evidence: EPSS ranks this CVE among the most likely to be exploited in the near term. EPSS rose +12.22% over the last day, indicating growing attacker interest. Mandatory action: High exploitation likelihood—assess exposure and prioritize remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2011-1473

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 55.49% 67.70% +12.22%
2 2026-05-18 64.64% 55.49% -9.15%
3 2026-05-08 64.64%

Full EPSS history (65 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2011-1473

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.0 2.0 MEDIUM
AV:N/AC:L/Au:N/C:N/I:N/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:P)
Partial availability impact.
10.0 2.9 [email protected]

Weakness enumeration for CVE-2011-1473

OS Trackers for CVE-2011-1473

vendor priority summary link
redhat low https://access.redhat.com/security/cve/CVE-2011-1473
ubuntu low CVE-2011-1473 low priority: Ubuntu including 2 source packages (openssl, openssl098), 16 status rows across 8 suites (hardy, lucid, maverick, natty, oneiric, precise, quantal, upstream): ignored 10, DNE 4, needs-triage 2. https://ubuntu.com/security/CVE-2011-1473

Affected software / configurations for CVE-2011-1473

Vendor Product Version Raw CPE
openssl openssl 0.9.8m cpe:2.3:a:openssl:openssl:0.9.8m:*:*:*:*:*:*:*
openssl openssl 0.9.8m cpe:2.3:a:openssl:openssl:0.9.8m:beta1:*:*:*:*:*:*
openssl openssl 0.9.8n cpe:2.3:a:openssl:openssl:0.9.8n:*:*:*:*:*:*:*
openssl openssl 0.9.8o cpe:2.3:a:openssl:openssl:0.9.8o:*:*:*:*:*:*:*
openssl openssl 0.9.8p cpe:2.3:a:openssl:openssl:0.9.8p:*:*:*:*:*:*:*
openssl openssl 0.9.8r cpe:2.3:a:openssl:openssl:0.9.8r:*:*:*:*:*:*:*
openssl openssl 0.9.8s cpe:2.3:a:openssl:openssl:0.9.8s:*:*:*:*:*:*:*
openssl openssl 0.9.8t cpe:2.3:a:openssl:openssl:0.9.8t:*:*:*:*:*:*:*
openssl openssl 0.9.8u cpe:2.3:a:openssl:openssl:0.9.8u:*:*:*:*:*:*:*
openssl openssl 0.9.8v cpe:2.3:a:openssl:openssl:0.9.8v:*:*:*:*:*:*:*
openssl openssl 0.9.8w cpe:2.3:a:openssl:openssl:0.9.8w:*:*:*:*:*:*:*
openssl openssl 0.9.8x cpe:2.3:a:openssl:openssl:0.9.8x:*:*:*:*:*:*:*
openssl openssl <= 0.9.8k cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:*

References for CVE-2011-1473

URL Tags
http://archives.neohapsis.com/archives/bugtraq/2014-02/0061.html
http://marc.info/?l=bugtraq&m=133951357207000&w=2
http://orchilles.com/2011/03/ssl-renegotiation-dos.html
http://vincent.bernat.im/en/blog/2011-ssl-dos-mitigation.html
http://www.educatedguesswork.org/2011/10/ssltls_and_computational_dos.html
http://www.ietf.org/mail-archive/web/tls/current/msg07553.html
http://www.ietf.org/mail-archive/web/tls/current/msg07564.html
http://www.ietf.org/mail-archive/web/tls/current/msg07567.html
http://www.ietf.org/mail-archive/web/tls/current/msg07576.html
http://www.ietf.org/mail-archive/web/tls/current/msg07577.html
http://www.openwall.com/lists/oss-security/2011/07/08/2
https://bugzilla.redhat.com/show_bug.cgi?id=707065
https://lists.apache.org/thread.html/142b93d261e8ac7c5ceffdce848d622404abc1c286bbc999f43a9e10%40%3Cdev.rocketmq.apache.org%3E
https://lists.apache.org/thread.html/6121becfdd23f9aeb675d5db80616536277d5931d6cde9dca292e509%40%3Cdev.rocketmq.apache.org%3E
https://lists.apache.org/thread.html/8be38d35654441140db8eb3f7433524b3653ac3fdc26e2fa94626a3a%40%3Cdev.rocketmq.apache.org%3E
https://lists.apache.org/thread.html/r13a07a09f98b2841193dbf17a47c7f09b464e0747a1d3e7298ad4c81%40%3Cdev.rocketmq.apache.org%3E
https://lists.apache.org/thread.html/r1e33410bb5c81536e7fe14b51fa83e7bfd9445db61fd10c134792bde%40%3Cdev.rocketmq.apache.org%3E
https://lists.apache.org/thread.html/r298a09a2b98446b27217d719e877c643b6d13fac0bcafe04696a446b%40%3Cdev.rocketmq.apache.org%3E
https://lists.apache.org/thread.html/r3822ad69442291562c2ab41132fc49780d269e8b52deb458b7060f6d%40%3Ccommits.rocketmq.apache.org%3E
https://lists.apache.org/thread.html/r5e595b91f00613dafa635852121d45b161e8b5c3eba4551aeccc6483%40%3Cdev.rocketmq.apache.org%3E
https://lists.apache.org/thread.html/r77fe575893261889b983e067293be72fa1f8c6305ede9fdbc404c514%40%3Cdev.rocketmq.apache.org%3E
https://lists.apache.org/thread.html/r8680f41bcdad13c3f267cb868b45e5fb1f57df8b39d25193f7d66500%40%3Cdev.rocketmq.apache.org%3E
https://lists.apache.org/thread.html/ra95c355827b3c96c8013ed8e0666c851581651be2524f3d28cd4fe71%40%3Cdev.rocketmq.apache.org%3E
https://lists.apache.org/thread.html/rc98eaa3f8223ac75aa5969f717954d8cbc9f3a9d8b7a6156a54fa557%40%3Cdev.rocketmq.apache.org%3E
https://lists.apache.org/thread.html/rf9e8ae0356af3ec4f7780ca651b770721d287d4d55f62f4f754e0a6f%40%3Cdev.rocketmq.apache.org%3E
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