# Google Guava: CompactHashMap/CompactHashSet/MapMakerInternalMap deserialization triggers uncontrolled memory allocation

Advisory record · `GHSA-xxph-c9ww-hj94`

- **Identifiers:** `GHSA-xxph-c9ww-hj94` · `CVE-2026-102554`
- **State:** Confirmed
- **Severity:** CVSS 8.2 High
- **Critical:** No
- **Weakness (CWE):** [CWE-400](https://cwe.mitre.org/data/definitions/400.html) · [CWE-502](https://cwe.mitre.org/data/definitions/502.html) · [CWE-770](https://cwe.mitre.org/data/definitions/770.html)
- **Tags:** [Denial of service](https://agentprime.io/advisories/tag/dos.md) · [Insecure deserialization](https://agentprime.io/advisories/tag/deserialization.md)
- **Published:** 27 Oct 2026
- **Updated:** 27 Oct 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 27 Oct 2026, 14:27 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `com.google.guava:guava` (Maven): affected `>=4.0, <33.7.2`; fixed in `33.7.2`

## Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

> Guava versions from 4.0 up to but not including 33.7.2 are affected. Deserializing a crafted Java serialized stream containing CompactHashMap, CompactHashSet, CompactLinkedHashMap, CompactLinkedHashSet or MapMakerInternalMap can make the JVM allocate very large arrays from a declared size, causing an OutOfMemoryError and a crash. An attacker who can supply serialized data to an application's ObjectInputStream.readObject() call can trigger this with a small payload. Upgrade to Guava 33.7.2, which contains the fix. The source gives few details on earlier individual releases.

Written 2 Nov 2026.

## Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

## Severity and exploitation

- 8.2 High, CVSS 4.0: `CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N`, from CNA (Google)

- **CISA KEV:** Not listed.
- **EPSS:** 0.0035, the 28th percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

- 31 Oct 2026, 14:16 UTC: First seen by agentprime
- 31 Oct 2026, 14:16 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/GHSA-xxph-c9ww-hj94)

## Sources

- [GitHub Advisory Database: GHSA-xxph-c9ww-hj94](https://github.com/advisories/GHSA-xxph-c9ww-hj94)
- [OSV: GHSA-xxph-c9ww-hj94](https://osv.dev/vulnerability/GHSA-xxph-c9ww-hj94)
- <https://github.com/google/guava/security/advisories/GHSA-xxph-c9ww-hj94>
- <https://nvd.nist.gov/vuln/detail/CVE-2026-102554>
- <https://github.com/google/guava/commit/b931fe9d6d5cf00bc55714ad3308d086f71850fe>
- <https://github.com/google/guava>
- <https://github.com/google/guava/releases/tag/v33.7.2>

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.

## Check whether this affects you

A Match means an installed version is in the affected range above. Most don’t affect the app; agentprime hasn’t analysed this one yet.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), ask your agent to check the project: `check_lockfile` sends a lockfile, `check_packages` a list of installed packages, and both return the Matches and the upgrades that clear them. `get_advisory` returns this record. Setup: <https://agentprime.io/mcp.md>
- In a browser: <https://agentprime.io/check/> reads your lockfile in the browser, never uploading it.
- Whether it touches your code, with file and line: the Claude Code plugin, <https://agentprime.io/plugin.md>
- As JSON: <https://api.agentprime.io/v1/advisories/GHSA-xxph-c9ww-hj94>, or `POST https://api.agentprime.io/v1/match` with your packages (<https://agentprime.io/api.md>)

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The web page: <https://agentprime.io/advisories/GHSA-xxph-c9ww-hj94/>. Everything for agents: <https://agentprime.io/llms.txt>.