# CVE-2026-110747: jackson-dataformat-protobuf: integer overflow in ProtobufParser._readStringKey() allows OutOfMemoryError from an 8-byte payload

Status: published. Published: 2026-10-28. Updated: 2026-11-06.

ProtobufParser._readStringKey() reads the length prefix of a protobuf map entry's string key into an attacker-controlled int and then checks (_inputPtr + len) <= _inputEnd using signed arithmetic. For values near Integer.MAX_VALUE the addition overflows to a negative value and the check passes even when the input contains no key data. The parser then calls _finishShortText(len), which expands the text buffer to the declared length via TextBuffer.expandCurrentSegment and Arrays.copyOf, throwing OutOfMemoryError: Requested array size exceeds VM limit.



An 8-byte malformed message containing a map entry with a declared key length of 0x7FFFFFFF is sufficient. Configured StreamReadConstraints, including maxStringLength, maxNameLength, maxDocumentLength and maxNestingDepth, do not prevent the failure. Applications running with -XX:+ExitOnOutOfMemoryError terminate the JVM.



This is the same integer-overflow pattern addressed for other call sites in the remediation associated with CVE-2026-104016 and CVE-2026-104017; the map-key call site was corrected on the 3.x branches only, leaving the corresponding 2.x branches unguarded. Release lines 2.18, 2.19 and 2.20 do not contain _readStringKey() and are not affected by this vector. No privileges or user interaction beyond the ability to submit data for parsing are required. The 3.0 release line and 3.1.0-3.1.5 / 3.2.0-3.2.1 do not contain _readStringKey() and are therefore not affected; the method first appears in 3.1.6 and 3.2.2, mirroring its introduction at 2.21.6 on the 2.x side.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- FasterXML / jackson-dataformat-protobuf (com.fasterxml.jackson.dataformat:jackson-dataformat-protobuf): ≥ 2.21.6; < 2.21.8 (affected, maven); 2.21.8 (unaffected, maven); ≥ 2.22.0; < 2.22.4 (affected, maven); 2.22.4 (unaffected, maven). Source: CNA: HeroDevs
- FasterXML / jackson-dataformat-protobuf (tools.jackson.dataformat:jackson-dataformat-protobuf): ≥ 3.1.6; < 3.1.8 (affected, maven); 3.1.8 (unaffected, maven); ≥ 3.2.2; < 3.2.4 (affected, maven); 3.2.4 (unaffected, maven). Source: CNA: HeroDevs

## Severity and prioritization

- CVSS 3.1: 7.5 (high); CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H; source: CNA: HeroDevs

- CISA KEV: No listing in collected sources

- EPSS: 0.39% as of 2026-11-06; percentile 33.04%

- SSVC: exploitation none; automatable yes; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-190

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://github.com/FasterXML/jackson-dataformats-binary/security/advisories/GHSA-fv7v-rrmh-4qcv (CNA: HeroDevs; vendor-advisory)

## Provenance

- CNA: HeroDevs: https://www.cve.org/CVERecord?id=CVE-2026-110747; retrieved 2026-11-06; source updated 2026-11-06

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-110747; retrieved 2026-11-06; source updated Not reported

Revision: 94e9022c622452e7f8d384f73bf1387407a8da42e2857c9ba81a079d3f95d7af

Canonical: https://y2.dev/cve/CVE-2026-110747

## Agent and API access

Public CVE pages, Markdown, and JSON are free to read without an account or API key.

- Public catalog: https://y2.dev/cve/index.json. Follow nextCursor with the same search, filters, sort, and limit (1–100). A null cursor marks the end.

- WebMCP: search_cve_disclosures, get_cve_disclosure, get_cve_page_markdown, get_y2_cve_access. Available in compatible browsers.

- Cyber API: https://api.y2.dev/api/v2/cyber/cves and https://api.y2.dev/api/v2/cyber/cves/{cveId}.

- Y2 Pro or Elite: create a workspace API key with the intel:cyber scope and send Authorization: Bearer <Y2_API_KEY>. Setup: https://y2.dev/docs/api/create-key.

- x402: Pay per request without an account or API key. Omit Authorization, read the HTTP 402 PAYMENT-REQUIRED challenge, validate its current requirements, and retry with PAYMENT-SIGNATURE through an authorized payment client. These browser tools never make payments. Guide: https://y2.dev/docs/api/x402.

- OpenAPI: https://y2.dev/api/openapi.yaml. Agent access metadata: https://y2.dev/cve/agent.json.

Collected public records only. Check source status for coverage and freshness.