CVE-2026-42216

OpenEXR provides the specification and reference implementation of the EXR file format, an image storage format for the motion picture industry. From versions 3.0.0 to before 3.2.9, 3.3.0 to before 3.3.11, and 3.4.0 to before 3.4.11, IDManifest::init() reconstructs strings from a prefix-compressed representation. If the previous string is longer than 255 bytes, the next string is expected to begin with a 2-byte prefix length. The code reads stringList[i][0] and stringList[i][1] without checking that the current string has at least two bytes. This issue has been patched in versions 3.2.9, 3.3.11, and 3.4.11.

Weakness

The product reads data past the end, or before the beginning, of the intended buffer.

Affected Software

Name	Vendor	Start Version	End Version
Openexr	Openexr	3.0.0 (including)	3.2.9 (excluding)
Openexr	Openexr	3.3.0 (including)	3.3.11 (excluding)
Openexr	Openexr	3.4.0 (including)	3.4.11 (excluding)
Red Hat Enterprise Linux 10	RedHat	openexr-0:3.1.10-8.el10_2.3	*
Red Hat Enterprise Linux 10.0 Extended Update Support	RedHat	openexr-0:3.1.10-8.el10_0.3	*
Red Hat Enterprise Linux 9	RedHat	openexr-0:3.1.1-3.el9_8.3	*
Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions	RedHat	openexr-0:3.1.1-2.el9_2.4	*
Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions	RedHat	openexr-0:3.1.1-2.el9_4.4	*
Red Hat Enterprise Linux 9.6 Extended Update Support	RedHat	openexr-0:3.1.1-3.el9_6.3	*
Openexr	Ubuntu	esm-infra/xenial	*
Openexr	Ubuntu	questing	*

Potential Mitigations

Assume all input is malicious. Use an “accept known good” input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, “boat” may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as “red” or “blue.”
Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code’s environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.
To reduce the likelihood of introducing an out-of-bounds read, ensure that you validate and ensure correct calculations for any length argument, buffer size calculation, or offset. Be especially careful of relying on a sentinel (i.e. special character such as NUL) in untrusted inputs.

https://cwe.mitre.org/data/definitions/540.html

NVD	https://nvd.nist.gov/vuln/detail/CVE-2026-42216
CWE	https://cwe.mitre.org/data/definitions/125.html

Out-of-bounds Read

Weakness

Affected Software

Potential Mitigations

References

CVE-2026-42216

Out-of-bounds Read

Weakness

Affected Software

Potential Mitigations

Related Attack Patterns

References