CVE-2021-25287

An issue was discovered in Pillow before 8.2.0. There is an out-of-bounds read in J2kDecode, in j2ku_graya_la.

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

Name	Vendor	Start Version	End Version
Pillow	Python	*	8.2.0 (excluding)
Red Hat Enterprise Linux 8	RedHat	python-pillow-0:5.1.1-16.el8	*
Pillow	Ubuntu	bionic	*
Pillow	Ubuntu	devel	*
Pillow	Ubuntu	esm-infra/xenial	*
Pillow	Ubuntu	focal	*
Pillow	Ubuntu	groovy	*
Pillow	Ubuntu	hirsute	*
Pillow	Ubuntu	impish	*
Pillow	Ubuntu	jammy	*
Pillow	Ubuntu	kinetic	*
Pillow	Ubuntu	lunar	*
Pillow	Ubuntu	mantic	*
Pillow	Ubuntu	noble	*
Pillow	Ubuntu	oracular	*
Pillow	Ubuntu	trusty	*
Pillow	Ubuntu	trusty/esm	*
Pillow	Ubuntu	upstream	*
Pillow	Ubuntu	xenial	*
Pillow-python2	Ubuntu	groovy	*
Python-imaging	Ubuntu	precise/esm	*

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.

NVD	https://nvd.nist.gov/vuln/detail/CVE-2021-25287
CWE	https://cwe.mitre.org/data/definitions/125.html

Out-of-bounds Read