CVE-2026-3989Public exploit

Code execution via unsafe crash-dump deserialization

Published Mar 12, 2026 · Updated Mar 12, 2026

Unsafe deserialization in SGLang 0.5.5 through 0.5.9 allows attackers to execute code via a crafted request-dump file. The read_records function in replay_request_dump.py passes each .pkl input directly to pickle.load, which invokes attacker-selected reduction callables. Execution requires an operator to replay a planted or socially supplied file and runs with the script process's privileges.

CVSS severity7.8
High
EPSS probability0.47%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Unsafe deserialization in SGLang 0.5.5 through 0.5.9 allows attackers to execute code via a crafted request-dump file. The read_records function in replay_request_dump.py passes each .pkl input directly to pickle.load, which invokes attacker-selected reduction callables. Execution requires an operator to replay a planted or socially supplied file and runs with the script process's privileges.

The record

CVE
CVE-2026-3989
Published
Mar 12, 2026
Updated
Mar 12, 2026
Vendor
SGLang
Product
SGLang
Classifications
CWE-502, T1204.002
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 12, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 12, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0.5.5 <=0.5.9

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

SGLang · SGLangversion=0.5.5 <=0.5.9

Published CVSS scores

7.8CISA-ADPCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-502Deserialization of Untrusted Data
T1204.002User Execution: Malicious File

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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