How severe is CVE-2026-29795?

CVE-2026-29795 has a CVSS score of 4/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2026-29795?

CVE-2026-29795 affects the following packages: stellar-xdr (crates.io). Ecosystems affected: crates.io.

How do I fix CVE-2026-29795?

Update stellar-xdr to 25.0.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-29795 is resolved across your whole dependency graph.

How do I detect CVE-2026-29795 in my crates.io dependencies?

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

How do I mitigate CVE-2026-29795 if there is no patch (or I can't update yet)?

Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Is CVE-2026-29795 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-29795 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-29795?

CVE-2026-29795 has an EPSS (Exploit Prediction Scoring System) score of 0.2%, placing it in the 13th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-29795?

CVE-2026-29795 is classified as CWE-770 (CWE-770). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2026-29795 published, and has it been updated?

CVE-2026-29795 was published on March 6, 2026 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🦀

🦀 crates.io

Not in CISA KEV

MEDIUM severity

CVE-2026-29795 — stellar-xdr

MEDIUMFix: stellar/rs-stellar-xdr@1f84001

CVE-2026-29795 is a medium-severity (CVSS 4) CWE-770 vulnerability in stellar-xdr. A fix is available for stellar-xdr — see the affected versions and patch details below.

stellar-xdr: `StringM::from_str` bypasses max length validation

Also known asGHSA-x57h-xx53-v53w

Published

Mar 6, 2026

Updated

Oct 28, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Nov 8, 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-2026-29795.

EPSS Exploitation Probability

via FIRST.org ↗

0.2%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs13th percentile — riskier than 13% of all scored CVEsHighest risk

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

1 pkg affected

🦀stellar-xdr

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

Description

Impact

StringM::from_str does not validate that the input length is within the declared maximum (MAX). Calling StringM::<N>::from_str(s) where s is longer than N bytes succeeds and returns an Ok value instead of Err(Error::LengthExceedsMax), producing a StringM that violates its length invariant.

This affects any code that constructs StringM values from string input using FromStr (including str::parse), and relies on the type's maximum length constraint being enforced. An oversized StringM could propagate through serialization, validation, or other logic that assumes the invariant holds.

All published versions of the stellar-xdr crate up to and including v25.0.0 are affected.

Patches

The fix is merged in #500. It replaces the direct Ok(Self(b)) construction with b.try_into(), which routes through TryFrom<Vec<u8>> and properly validates the length — matching the pattern already used by BytesM::from_str.

Users should upgrade to the first release containing this fix once published (the next release after v25.0.0).

Workarounds

Validate the byte length of string input before calling StringM::from_str, or construct StringM values via StringM::try_from(s.as_bytes().to_vec()) which correctly enforces the length constraint.

References

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🦀crates.io	`stellar-xdr`	all versions	25.0.1`cargo update -p stellar-xdr --precise 25.0.1`

Affected Products

1 product · 1 configurations

Application

stellar-xdrstellar

< 25.0.1

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for stellar-xdr, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update stellar-xdr to 25.0.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-29795 is resolved across your whole dependency graph.
Workarounds
Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Frequently Asked Questions

### Impact `StringM::from_str` does not validate that the input length is within the declared maximum (`MAX`). Calling `StringM::<N>::from_str(s)` where `s` is longer than `N` bytes succeeds and returns an `Ok` value instead of `Err(Error::LengthExceedsMax)`, producing a `StringM` that violates its length invariant. This affects any code that constructs `StringM` values from string input using `FromStr` (including `str::parse`), and relies on the type's maximum length constraint being enforced. An oversized `StringM` could propagate through serialization, validation, or other logic that assu