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MEDIUM severity

CVE-2026-2303 — mongo-driver

MEDIUM

CVE-2026-2303 is a medium-severity (CVSS 6.5) CWE-183 vulnerability in go.mongodb.org/mongo-driver. A fix is available for go.mongodb.org/mongo-driver — see the affected versions and patch details below.

mongo-go-driver has Heap Out-of-Bounds Read in GSSAPI Error Handling

Also known asGO-2026-5327
Published
Updated
Affected
2 pkgs
Patched
2 / 2
Exploits
None indexed
Exploitation data as of Nov 5, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

  • CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-2303.

EPSS Exploitation Probability

via FIRST.org ↗
0.3%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs25th percentile — riskier than 25% of all scored CVEsHighest risk
0.00%0.27%0.55%0.82%0.1%0.3%May 26Sep 26Nov 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

2 pkgs affected
🐹go.mongodb.org/mongo-driver🐹go.mongodb.org/mongo-driver/v2

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.

Description

The mongo-go-driver repository contains CGo bindings for GSSAPI (Kerberos) authentication on Linux and macOS. The C wrapper implementation contains a heap out-of-bounds read vulnerability due to incorrect assumptions about string termination in the GSSAPI standard. Since GSSAPI buffers are not guaranteed to be null-terminated or have extra padding, this results in reading one byte past the allocated heap buffer.

Affected Packages

2 total 2 fixed
EcosystemPackageVulnerable rangeFix
🐹Gogo.mongodb.org/mongo-driverall versions1.17.7go get go.mongodb.org/mongo-driver@v1.17.7
🐹Gogo.mongodb.org/mongo-driver/v2all versions2.4.2go get go.mongodb.org/mongo-driver/v2@v2.4.2

Detection & mitigation playbook

Open-source dependency

  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for go.mongodb.org/mongo-driver, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update go.mongodb.org/mongo-driver to 1.17.7 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-2303 is resolved across your whole dependency graph.

  3. Workarounds

    Constrain what reaches the vulnerable code: limit the size and shape of untrusted input, isolate the affected component in a sandboxed or least-privileged process, and enable the platform's memory-safety mitigations (ASLR, stack protector, hardened allocator) so an out-of-bounds access is more likely to fail closed than to be exploitable.

Frequently Asked Questions

The mongo-go-driver repository contains CGo bindings for GSSAPI (Kerberos) authentication on Linux and macOS. The C wrapper implementation contains a heap out-of-bounds read vulnerability due to incorrect assumptions about string termination in the GSSAPI standard. Since GSSAPI buffers are not guaranteed to be null-terminated or have extra padding, this results in reading one byte past the allocated heap buffer.
O3 Security · Impact-Aware SCA

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CVE-2026-2303: mongo-driver — Fixed in 1.17.7