GHSA-649x-hxfx-57j2 is a medium-severity (CVSS 4.9) CWE-835 vulnerability in github.com/vitessio/vitess. A fix is available for github.com/vitessio/vitess — see the affected versions and patch details below.
Vitess vulnerable to infinite memory consumption and vtgate crash
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 GHSA-649x-hxfx-57j2.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
GHSA-649x-hxfx-57j2 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,166 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
github.com/vitessio/vitess🐹github.com/vitessio/vitess🐹github.com/vitessio/vitess🐹vitess.io/vitess🐹vitess.io/vitess🐹vitess.io/vitessReal-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
Summary
When executing the following simple query, the vtgate will go into an endless loop that also keeps consuming memory and eventually will OOM.
Details
When running the following query, the evalengine will try evaluate it and runs forever.
select _utf16 0xFF
The source of the bug lies in the collation logic that we have. The bug applies to all utf16, utf32 and ucs2 encodings. In general, the bug is there for any encoding where the minimal byte length for a single character is more than 1 byte.
The decoding functions for these collations all implement logic like the following to enforce the minimal character length:
The problem is that all the callers of DecodeRune expect progress by returning the number of bytes consumed. This means that if there's only 1 byte left in an input, it will here return still 0 and the caller(s) don't consume the character.
One example of such a caller is the following:
The logic here moves forward the pointer in the input []byte but if DecodeRune returns 0 in case of error, it will keep running forever. The OOM happens since it keeps adding the ? as the invalid character to the destination buffer infinitely, growing forever until it runs out of memory.
The fix here would be to always return forward progress also on invalid strings.
There's also a separate bug here that even if progress is guaranteed, select _utf16 0xFF will return the wrong result currently. MySQL will pad here the input when the _utf16 introducer is used with leading 0x00 bytes and then decode to UTF-16, resulting in the output of ÿ here.
PoC
select _utf16 0xFF
Impact
Denial of service attack by triggering unbounded memory usage.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/vitessio/vitess | ≥ 19.0.0&&< 19.0.4 | 19.0.4go get github.com/vitessio/vitess@v19.0.4 |
| 🐹Go | github.com/vitessio/vitess | ≥ 18.0.0&&< 18.0.5 | 18.0.5go get github.com/vitessio/vitess@v18.0.5 |
| 🐹Go | github.com/vitessio/vitess | all versions | 17.0.7go get github.com/vitessio/vitess@v17.0.7 |
| 🐹Go | vitess.io/vitess | all versions | 0.17.7go get vitess.io/vitess@v0.17.7 |
| 🐹Go | vitess.io/vitess | ≥ 0.18.0&&< 0.18.5 | 0.18.5go get vitess.io/vitess@v0.18.5 |
| 🐹Go | vitess.io/vitess | ≥ 0.19.0&&< 0.19.4 | 0.19.4go get vitess.io/vitess@v0.19.4 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/vitessio/vitess, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/vitessio/vitess to 19.0.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-649x-hxfx-57j2 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-649x-hxfx-57j2 can be triaged on real exposure rather than presence alone.
Tailored to GHSA-649x-hxfx-57j2. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-649x-hxfx-57j2 in your dependencies?
O3 Security finds GHSA-649x-hxfx-57j2 across Go dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.