GHSA-xgrm-4fwx-7qm8 CVE-2026-33815 GO-2026-4771

pgx contains memory-safety vulnerability

Critical Go

Severity: 9.8 / 10; Critical · CVSS 3.1
Exploit chance (EPSS): 0.60%; Chance of exploitation in the next 30 days. Higher than 48.97% of scored vulnerabilities.
Known exploited: No; Not in CISA's catalog
Weakness: CWE-787 Out-of-bounds Write
Fix: 5.9.0; Upgrade github.com/jackc/pgx/v5 to this version or later

Description

pgx is a pure Go driver and toolkit for PostgreSQL. pgx prior to v5.9.0 contains a memory-safety vulnerability.

Affected versions

Go

Package	Vulnerable	Fixed in
github.com/jackc/pgx/v5	`< 5.9.0`	`5.9.0`
github.com/jackc/pgx/v5	`< 5.9.0`	`5.9.0`

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.

github.com/jackc/pgx/v5 Go → `5.9.0`

go

go get github.com/jackc/pgx/v5@v5.9.0 && go mod tidy

Severity breakdown

CVSS 3.1 9.8

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

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

Weakness

CWE-787: Out-of-bounds Write

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

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.

References

Advisories

Fixes and patches

github.com/jackc/pgx/commit/6dbad4cafdb8a4daab7ff79c858c95da4b6109e8

Timeline

Apr 7, 2026 Published
Oct 26, 2026 Last updated by the source
Oct 31, 2026 Latest EPSS score

Advisory	Severity	Why it's related
GHSA-j88v-2chj-qfwx pgx: SQL Injection via placeholder confusion with dollar quoted string literals	Low	Also affects github.com/jackc/pgx/v5
GHSA-9jj7-4m8r-rfcm Memory-safety vulnerability in github.com/jackc/pgx/v5.	Critical	Also affects github.com/jackc/pgx/v5
GHSA-fqpg-rq76-99pq Panic in Pipeline when PgConn is busy or closed in github.com/jackc/pgx	Medium	Also affects github.com/jackc/pgx/v5
GHSA-mrww-27vc-gghv pgproto3 SQL Injection via Protocol Message Size Overflow	High	Also affects github.com/jackc/pgx/v5
GHSA-78g4-xqwv-q3g8 Pillow: Bundled libopenjp2 2.5.4 in all wheels since 11.1.0 carries OSV-2025-219 heap-buffer-overflow write reachable from Image.open().load()	High	Same weakness, CWE-787
GHSA-9v8h-qqgm-4m35 Brotli: Out-of-bounds write in the Brotli decoder ("Node2Shell") also affects the PyPI Brotli package	Critical Known exploited	Same weakness, CWE-787
GHSA-g7cr-3p24-7wf7 Pillow: Heap buffer overflow writing JPEG comment after ICC profile fills buffer	High	Same weakness, CWE-787
GHSA-v9pv-5gc8-w2m6 Pillow multi-frame loaders can reuse stale native image storage after mode transitions	Critical	Same weakness, CWE-787

Credits: dor-hayun, mitar

Is this in your code?

MergeHarbor checks every repository's dependencies against this database, ranks what matters by exploitability and reachability, routes it to the owning team and opens the fix pull request.

Check your repos with MergeHarbor