CVE-2022-31159 is a high-severity (CVSS 7.9) Path Traversal vulnerability in com.amazonaws:aws-java-sdk-s3. 1 public exploit or proof-of-concept reference is indexed, so weaponization risk is real. A fix is available for com.amazonaws:aws-java-sdk-s3 — see the affected versions and patch details below.
Partial Path Traversal in com.amazonaws:aws-java-sdk-s3
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
- A successful exploit gives an attacker total control of the affected component, not partial access.
Exploitation and automatability from CISA’s SSVC triage for CVE-2022-31159.
EPSS Exploitation Probability
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
com.amazonaws:aws-java-sdk-s3Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.
Description
Overview
A partial-path traversal issue exists within the downloadDirectory method in the AWS S3 TransferManager component of the AWS SDK for Java v1. Applications using the SDK control the destinationDirectory argument, but S3 object keys are determined by the application that uploaded the objects. The downloadDirectory method allows the caller to pass a filesystem object in the object key but contained an issue in the validation logic for the key name. A knowledgeable actor could bypass the validation logic by including a UNIX double-dot in the bucket key. Under certain conditions, this could permit them to retrieve a directory from their S3 bucket that is one level up in the filesystem from their working directory.
This issue’s scope is limited to directories whose name prefix matches the destinationDirectory. E.g. for destination directory/tmp/foo, the actor can cause a download to /tmp/foo-bar, but not /tmp/bar.
Versions of the AWS Java SDK for S3 v1 before and including v1.12.260 are affected by this issue.
Impact
If com.amazonaws.services.s3.transfer.TransferManager::downloadDirectory is used to download an untrusted buckets contents, the contents of that bucket can be written outside of the intended destination directory.
Root Cause
The com.amazonaws.services.s3.transfer.TransferManager::downloadDirectory contains a partial-path traversal vulnerability.
This is due to the guard logic in leavesRoot containing an insufficient protection against partial-path traversal.
The application controls the localBaseDirectory argument, but the key comes from the AWS bucket entry (ie. can be attacker controlled). The above bit of logic can be bypassed with the following payloads:
// The following will return 'false', although the attacker value will "leave" the `/usr/foo` directory
leavesRoot(new File("/usr/foo"), "/../foo-bar/bar")
This guard is used here which should guard against path traversal, however leavesRoot is an insufficient guard:
True Root cause
If the result of parent.getCanonicalPath() is not slash terminated it allows for partial path traversal.
Consider
"/usr/outnot".startsWith("/usr/out"). The check is bypassed althoughoutnotis not under theoutdirectory. The terminating slash may be removed in various places. On Linuxprintln(new File("/var/"))returns/var, butprintln(new File("/var", "/"))-/var/, howeverprintln(new File("/var", "/").getCanonicalPath())-/var. - @JarLob (Jaroslav Lobačevski)
Patches
Upgrade to the AWS SDK for Java >= 1.12.261, if you are on a version < 1.12.261.
Workarounds
When calling com.amazonaws.services.s3.transfer.TransferManager::downloadDirectory pass a KeyFilter that forbids S3ObjectSummary objects that getKey method return a string containing the substring .. .
References
Similar vulnerabilities:
- ESAPI (The OWASP Enterprise Security API) - https://nvd.nist.gov/vuln/detail/CVE-2022-23457
For more information
If you have any questions or comments about this advisory, please contact AWS's Security team.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | com.amazonaws:aws-java-sdk-s3 | all versions | 1.12.261com.amazonaws:aws-java-sdk-s3:1.12.261 |
Affected Products
aws-sdk-javaamazonResearch use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for com.amazonaws:aws-java-sdk-s3, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update com.amazonaws:aws-java-sdk-s3 to 1.12.261 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2022-31159 is resolved across your whole dependency graph.
Workarounds
Resolve every user-supplied path to its canonical form and reject anything that escapes the intended directory, and run the component under an account that has no read or write access outside the directory it legitimately serves.
Frequently Asked Questions
Is CVE-2022-31159 in your dependencies?
Find it across Maven, including transitive dependencies.