How to Fix CVE-2026-4738: Memory Corruption in gdal
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*By Sai Kiran Pandrala*
| Severity | CVSS 9.4 - Critical |
|---|---|
| Actively exploited? | Not currently listed in CISA KEV |
| Affected | 0 < 3.11.0 |
| Fixed in | See vendor advisory |
| Type (CWE) | CWE-119: Improper Restriction of Operations within the Bounds of a Memory Buffer |
What is CVE-2026-4738?
CVE-2026-4738 is a memory corruption flaw in gdal. A malformed input corrupts memory state in a way that leads to remote code execution under realistic conditions. Vendor description: Improper Restriction of Operations within the Bounds of a Memory Buffer vulnerability in OSGeo gdal (frmts/zlib/contrib/infback9 modules). This vulnerability is associated with program files inftree9.C.
Why this CVE matters
Memory-corruption flaws in a network-facing service are a perennial target for exploit developers. Modern mitigations slow but rarely stop a determined attacker, especially against embedded or appliance-class targets.
For deployments of gdal that have been exposed to the public internet during the disclosure window, the operating assumption should be that scanning has already happened. Even where exploitation has not been publicly observed, scanning for the vulnerable fingerprint is cheap and routine. Patching closes the door; log review and credential rotation close out the rest of the response.
Am I affected?
You are affected if your installation matches any of these version ranges:
- gdal: 0 < 3.11.0
Check your installed version against the list above. If you cannot determine the version, treat the system as affected and follow the upgrade path below.
Open gdal's About dialog or run the vendor-documented version-check command. Compare the result against the affected ranges in the advisory.
How to fix CVE-2026-4738
- Read the vendor advisory in full: https://github.com/OSGeo/gdal/pull/12244
- Upgrade gdal to the patched build listed in the vendor advisory.
- Back up the configuration (and database, where applicable) before upgrading.
- Apply the patch in a maintenance window. For HA pairs, upgrade the standby node first, fail over, then upgrade the former primary.
- Restart the affected service so the patched binary loads, then verify the new version (see verification section).
Open-source library upgrade
The vendor advisory (https://github.com/OSGeo/gdal/pull/12244) names the patched release as the build named in the vendor advisory (https://github.com/OSGeo/gdal/pull/12244). Pull the
fixed version through whichever ecosystem actually ships gdal.
# Vendor advisory: https://github.com/OSGeo/gdal/pull/12244
# npm / pnpm / yarn
npm install gdal@latest
npm ls gdal
# Or pin to the patched version named in the advisory
npm install gdal@<patched-version>
# pip / Poetry
pip install --upgrade "gdal"
pip show gdal | grep -i version
poetry add "gdal@^<patched-version>"
# Go modules
go get example.com/gdal@<patched-version>
go mod tidy
# Rust crates
cargo update -p gdal
# Composer
composer require vendor/gdal:^<patched-version>
# Vendor advisory: https://github.com/OSGeo/gdal/pull/12244
# Container image: rebuild against the patched base and roll the deployment.
docker pull <your-registry>/gdal:<patched-tag>
docker stop <app> && docker rm <app>
docker run -d --name <app> <your-registry>/gdal:<patched-tag>
# Kubernetes
kubectl set image deployment/<deployment-name> <container>=<your-registry>/gdal:<patched-tag>
kubectl rollout status deployment/<deployment-name>
Linux package upgrade
The vendor advisory (https://github.com/OSGeo/gdal/pull/12244) names the patched build as the build named in the vendor advisory (https://github.com/OSGeo/gdal/pull/12244).
# Ubuntu / Debian
sudo apt-get update
sudo apt-get install --only-upgrade gdal
dpkg -s gdal | grep -i version
# RHEL / Rocky / AlmaLinux / Fedora
sudo dnf upgrade --refresh gdal -y
rpm -q gdal
# openSUSE
sudo zypper refresh && sudo zypper update gdal
# Restart the service that loads the patched binary
sudo systemctl restart gdal 2>/dev/null || true
sudo systemctl status gdal --no-pager 2>/dev/null || true
# Vendor advisory: https://github.com/OSGeo/gdal/pull/12244
# Container deployments: rebuild with the patched package layer, then roll the workload.
docker pull <your-registry>/gdal:<patched-tag>
docker stop <app> && docker rm <app>
docker run -d --name <app> <your-registry>/gdal:<patched-tag>
# Kubernetes
kubectl set image deployment/<deployment-name> gdal=<your-registry>/gdal:<patched-tag>
kubectl rollout status deployment/<deployment-name>
Verify the fix landed
# Vendor advisory: https://github.com/OSGeo/gdal/pull/12244
# 1. Compare the running version against the fixed build named above.
# (Replace the version probe with the platform-specific command from the block above.)
# 2. Re-scan with your vulnerability scanner (Nessus, Qualys, Tenable, OpenVAS).
# The scanner should no longer flag this CVE on the patched target.
# 3. Inspect recent service / kernel logs for crash loops or rollback events.
journalctl -u <service> --since "10 minutes ago"
dmesg --since "10 minutes ago"
If you cannot patch immediately
Restrict access to the management interface to trusted internal IP addresses only. Block public access at the firewall and require VPN for any remote administration. Apply the patch as soon as a maintenance window allows.
How to verify the fix worked
- After applying the patch, verify the running version in the product's admin UI or via the vendor-documented CLI command.
- Confirm the patched build matches the version listed in the vendor advisory.
- Run an authenticated vulnerability scan with a current signature set and confirm the scanner no longer flags CVE-2026-4738.
- Review logs for the entire pre-patch window for indicators of compromise listed in the vendor or CISA advisory.
- Confirm any network-layer mitigations that were applied as a stopgap have been reverted (or left in place intentionally) once the patch is verified.
If your installation was internet-reachable during the disclosure window, treat log review as part of the remediation rather than an optional follow-up. Look for repeated service restarts, crash logs from the affected daemon, and core files generated around the time of any anomalous traffic. A memory-corruption flaw used for exploitation often leaves a trail of failed attempts before the successful one.
Frequently asked questions
Is CVE-2026-4738 being exploited in the wild?
Public exploitation has not been confirmed by CISA at the time of writing. Treat the patch as time-sensitive anyway; reports often lag actual abuse.
Will a WAF or IDS rule fully mitigate CVE-2026-4738?
No. Network-layer filters can reduce noise and slow opportunistic scanners, but they will not stop a determined attacker. The vendor patch is the only durable fix.
How long should I plan for the upgrade?
Typical vendor-documented upgrade windows for gdal run from a few minutes to under an hour depending on cluster size. Test in a staging environment first and follow the vendor's documented HA upgrade order.
References
- Official vendor advisory: https://github.com/OSGeo/gdal/pull/12244
- NVD entry: https://nvd.nist.gov/vuln/detail/CVE-2026-4738
- CISA KEV catalog: https://www.cisa.gov/known-exploited-vulnerabilities-catalog
*This guide was assembled from the official vendor advisory, the NVD record, and the CISA KEV catalog entry on 2026-05-25. Always confirm against the vendor advisory before applying changes in production.*