MessagePack for C# is a MessagePack serializer for C#. Prior to 2.5.301 and 3.1.7, runtime-generated union deserializers emitted by DynamicUnionResolver do not call MessagePackSecurity.DepthStep(ref reader) and do not decrement reader.Depth around recursive deserialization and skip paths. This means union deserialization does not consistently participate in the maximum object graph depth enforcement that protects other recursive formatter paths. For unknown union keys, the emitted deserializer calls reader.Skip() on attacker-controlled data without an enclosing depth step. This vulnerability is fixed in 2.5.301 and 3.1.7.
CVE-2026-48513
This high-severity CVE scores 7.5 under NVD CVSS v3. EPSS exploit probability: 0.2%, top 86% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
- High severity, but no confirmed exploitation yet
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 7.5
- EG Score
- 7.5(medium)
- EPSS
- 13.9%
- KEV
- Not listed
Published
June 22, 2026
Last Modified
June 25, 2026
Advisory Details (1)
Auto-updated Jun 23, 2026DynamicUnionResolver generated deserializers miss depth enforcement · Advisory · MessagePack-CSharp/MessagePack-CSharp · GitHub
https://github.com/MessagePack-CSharp/MessagePack-CSharp/security/advisories/GHSA-wfr3-xj75-pfwhVendor Advisories for CVE-2026-48513(1)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 19× in last 7d / 45× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-07-06 21:51 UTCEG score recompute
- 2026-07-06 16:27 UTCEPSS rescore
- 2026-07-06 09:29 UTCEG score recompute
- 2026-07-06 02:23 UTCEPSS rescore
- 2026-07-05 20:37 UTCEG score recompute
- 2026-07-05 08:14 UTCEG score recompute
- 2026-07-05 02:30 UTCEPSS rescore
- 2026-07-04 19:52 UTCEG score recompute
- 2026-07-04 07:31 UTCEG score recompute
- 2026-07-04 06:31 UTCEPSS rescore
- 2026-07-03 18:59 UTCEG score recompute
- 2026-07-03 06:38 UTCEG score recompute
- 2026-07-02 18:14 UTCEG score recompute
- 2026-07-02 05:51 UTCEG score recompute
- 2026-07-01 17:28 UTCEG score recompute
- 2026-07-01 15:07 UTCEPSS rescore
- 2026-07-01 05:05 UTCEG score recompute
- 2026-06-30 23:22 UTCEPSS rescore
- 2026-06-30 16:43 UTCEG score recompute
- 2026-06-30 04:21 UTCEG score recompute
- 2026-06-29 15:59 UTCEG score recompute
- 2026-06-29 14:06 UTCEPSS rescore
- 2026-06-29 14:06 UTCEPSS rescore
- 2026-06-29 03:37 UTCEG score recompute
- 2026-06-28 15:13 UTCEG score recompute
Show 20 moreShow fewer
- 2026-06-28 14:07 UTCEPSS rescore
- 2026-06-28 04:56 UTCEPSS rescore
- 2026-06-28 04:56 UTCEPSS rescore
- 2026-06-28 02:52 UTCEG score recompute
- 2026-06-27 14:30 UTCEG score recompute
- 2026-06-27 03:08 UTCEPSS rescore
- 2026-06-27 02:08 UTCEG score recompute
- 2026-06-26 13:45 UTCEG score recompute
- 2026-06-26 01:24 UTCEG score recompute
- 2026-06-25 13:49 UTCEPSS rescore
- 2026-06-25 13:02 UTCEG score recompute
- 2026-06-25 00:40 UTCEG score recompute
- 2026-06-24 14:05 UTCEPSS rescore
- 2026-06-24 12:19 UTCEG score recompute
- 2026-06-23 23:56 UTCEG score recompute▲ 1.20
- 2026-06-23 21:33 UTCEPSS rescore
- 2026-06-23 21:33 UTCEPSS rescore
- 2026-06-23 17:33 UTCNVD updateCVSS v3 → 7.5 · severity → HIGH
- 2026-06-23 00:01 UTCEG score recompute
- 2026-06-23 00:00 UTCMITRE cvelistV5first tracked
Related CVEs(same CWE)
Frequently asked(5)
What is CVE-2026-48513?
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What is the CVSS score of CVE-2026-48513?
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Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2026-48513
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