Issue summary: A type confusion vulnerability exists in the TimeStamp Response
verification code where an ASN1_TYPE union member is accessed without first
validating the type, causing an invalid or NULL pointer dereference when
processing a malformed TimeStamp Response file.
Impact summary: An application calling TS_RESP_verify_response() with a
malformed TimeStamp Response can be caused to dereference an invalid or
NULL pointer when reading, resulting in a Denial of Service.
The functions ossl_ess_get_signing_cert() and ossl_ess_get_signing_cert_v2()
access the signing cert attribute value without validating its type.
When the type is not V_ASN1_SEQUENCE, this results in accessing invalid memory
through the ASN1_TYPE union, causing a crash.
Exploiting this vulnerability requires an attacker to provide a malformed
TimeStamp Response to an application that verifies timestamp responses. The
TimeStamp protocol (RFC 3161) is not widely used and the impact of the
exploit is just a Denial of Service. For these reasons the issue was
assessed as Low severity.
The FIPS modules in 3.5, 3.4, 3.3 and 3.0 are not affected by this issue,
as the TimeStamp Response implementation is outside the OpenSSL FIPS module
boundary.
OpenSSL 3.6, 3.5, 3.4, 3.3, 3.0 and 1.1.1 are vulnerable to this issue.
OpenSSL 1.0.2 is not affected by this issue.
SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; 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 none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table
BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; 60 days if it is not.
In CISA KEV no (CISA's KEV catalog) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it