GHSA-8gq9-2x98-w8hf CVE-2022-1941 PYSEC-2026-899

protobuf-cpp and protobuf-python have potential Denial of Service issue

High PyPI

Severity: 7.5 / 10; High · CVSS 3.1
Exploit chance (EPSS): 1.51%; Chance of exploitation in the next 30 days. Higher than 74.47% of scored vulnerabilities.
Known exploited: No; Not in CISA's catalog
Weakness: CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer; CWE-1286 Improper Validation of Syntactic Correctness of Input
Fix: 3.18.3; Upgrade protobuf to this version or later

Description

Summary

A message parsing and memory management vulnerability in ProtocolBuffer’s C++ and Python implementations can trigger an out of memory (OOM) failure when processing a specially crafted message, which could lead to a denial of service (DoS) on services using the libraries.

Reporter: ClusterFuzz

Affected versions: All versions of C++ Protobufs (including Python) prior to the versions listed below.

Severity & Impact

As scored by google
Medium 5.7 - CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Asscored byt NIST
High 7.5 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

A small (~500 KB) malicious payload can be constructed which causes the running service to allocate more than 3GB of RAM.

Proof of Concept

For reproduction details, please refer to the unit test that identifies the specific inputs that exercise this parsing weakness.

Mitigation / Patching

Please update to the latest available versions of the following packages:

protobuf-cpp (3.18.3, 3.19.5, 3.20.2, 3.21.6)
protobuf-python (3.18.3, 3.19.5, 3.20.2, 4.21.6)

Affected versions

PyPI

Package	Vulnerable	Fixed in
protobuf	`< 3.18.3`	`3.18.3`
protobuf	`>= 3.19.0, < 3.19.5`	`3.19.5`
protobuf	`>= 3.20.0, < 3.20.2`	`3.20.2`
protobuf	`>= 4.0.0, < 4.21.6`	`4.21.6`
protobuf	`< 3.18.3` `>= 3.19.0, < 3.19.5` `>= 3.20.0, < 3.20.2` `>= 4.0.0, < 4.21.6`	`3.18.3` `3.19.5` `3.20.2` `4.21.6`

How to fix

Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.

protobuf PyPI → `3.18.3`

pip

pip install --upgrade "protobuf>=3.18.3"

poetry

poetry add "protobuf>=3.18.3"

uv

uv add "protobuf>=3.18.3"

Severity breakdown

CVSS 3.1 7.5

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack vector: Network
Attack complexity: Low
Privileges required: None
User interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: High

Weakness

CWE-119: Improper Restriction of Operations within the Bounds of a Memory Buffer

The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.

How to prevent it

Requirements: Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, many languages that perform their own memory management, such as Java and Perl, are not subject to buffer overflows. Other languages, such as Ada and C#, typically provide overflow protection, but the protection can be disabled by the programmer. Be wary that a language's interface to native code may still be subject to overflows, even if the language itself is theoretically safe.
Architecture and Design: Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. Examples include the Safe C String Library (SafeStr) by Messier and Viega [REF-57], and the Strsafe.h library from Microsoft [REF-56]. These libraries provide safer versions of overflow-prone string-handling functions.
Operation, Build and Compilation: Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index checking. D3-SFCV (Stack Frame Canary Validation) from D3FEND [REF-1334] discusses canary-based detection in detail.
Implementation: Consider adhering to the following rules when allocating and managing an application's memory: Double check that the buffer is as large as specified. When using functions that accept a number of bytes to copy, such as strncpy(), be aware that if the destination buffer size is equal to the source buffer size, it may not NULL-terminate the string. Check buffer boundaries if accessing the buffer in a loop and make sure there is no danger of writing past the allocated space. If necessary, truncate all input strings to a reasonable length before passing them to the copy and concatenation functions.
Operation, Build and Compilation: Run or compile the software using features or extensions that randomly arrange the positions of a program's executable and libraries in memory. Because this makes the addresses unpredictable, it can prevent an attacker from reliably jumping to exploitable code. Examples include Address Space Layout Randomization (ASLR) [REF-58] [REF-60] and Position-Independent Executables (PIE) [REF-64]. Imported modules may be similarly realigned if their default memory addresses conflict with other modules, in a process known as "rebasing" (for Windows) and "prelinking" (for Linux) [REF-1332] using randomly generated addresses. ASLR for libraries cannot be used in conjunction with prelink since it would require relocating the libraries at run-time, defeating the whole purpose of prelinking. For more information on these techniques see D3-SAOR (Segment Address Offset Randomization) from D3FEND [REF-1335].
Operation: Use a CPU and operating system that offers Data Execution Protection (using hardware NX or XD bits) or the equivalent techniques that simulate this feature in software, such as PaX [REF-60] [REF-61]. These techniques ensure that any instruction executed is exclusively at a memory address that is part of the code segment. For more information on these techniques see D3-PSEP (Process Segment Execution Prevention) from D3FEND [REF-1336].
Implementation: Replace unbounded copy functions with analogous functions that support length arguments, such as strcpy with strncpy. Create these if they are not available.

CWE-1286: Improper Validation of Syntactic Correctness of Input

The product receives input that is expected to be well-formed - i.e., to comply with a certain syntax - but it does not validate or incorrectly validates that the input complies with the syntax.

How to prevent it

Implementation: 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.

References

Advisories

Packages

Timeline

Sep 22, 2022 Published
Jul 8, 2026 Last updated by the source
Nov 1, 2026 Latest EPSS score

Advisory	Severity	Why it's related
GHSA-7gcm-g887-7qv7 protobuf affected by a JSON recursion depth bypass	High	Also affects protobuf
GHSA-8qvm-5x2c-j2w7 protobuf-python has a potential Denial of Service issue	High	Also affects protobuf
PYSEC-2022-48 Withdrawn Advisory: NULL Pointer Dereference in Protocol Buffers	High	Also affects protobuf
GHSA-jwvw-v7c5-m82h protobuf susceptible to buffer overflow	High	Also affects protobuf
CVE-2026-88779 Vulnerability in NetScaler ADC and NetScaler Gateway.	High Known exploited	Same weakness, CWE-119
CVE-2026-88772 Vulnerability in Citrix NetScaler ADC and Citrix NetScaler Gateway.	Critical Known exploited	Same weakness, CWE-119
GHSA-55f6-pf8r-c2f4 Open Babel has out-of-bounds write in MOPAC translationVectors[] (UNIT CELL TRANSLATION)	High	Same weakness, CWE-119
GHSA-f8h2-c479-vqxf Open Babel has out-of-bounds write in MSI translationVectors[]	High	Same weakness, CWE-119

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