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Vulnerabilities

Vulnerability · AZL-113021

CVE-2026-48510 affecting package python-msgpack 1.2.3-1

Published Jun 22, 2026 · catalog updated Nov 10, 2026 · affecting package python-msgpack 1.2.3-1

Last checked Nov 11, 2026. A connected source was read within the last 7 days.

Open the advisory

Exploitation likelihood is not on this record for AZL-113021. A missing EPSS score is not a low risk. Compare affecting package python-msgpack 1.2.3-1 with the linked advisory before you change production.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (affecting package python-msgpack 1.2.3-1).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
  • EPSS is missing. A missing score is not a low risk.
Severity
Unknown—
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
Awaiting synchronization with FIRST
Remediation
Not established
Affected products
Azure Linux:3 python-msgpack

MessagePack for C# is a MessagePack serializer for C#. Prior to 2.5.301 and 3.1.7, when MessagePack-CSharp decompresses Lz4Block or Lz4BlockArray payloads, it reads declared uncompressed lengths from the wire and allocates output buffers based on those lengths before validating that the compressed data is valid or that the declared expansion is reasonable. A small payload can claim a very large uncompressed length and force a large allocation before LZ4 decoding begins. This vulnerability is fixed in 2.5.301 and 3.1.7.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • Azure Linux:3 python-msgpack0 → 1.2.3-1

How to fix AZL-113021

  • Upgrade

    AZL-113021 lists a fix boundary at 1.2.3-1. Compare the installed build with that boundary before you change production.

  • Version check

    Fixed in 1.2.3-1

  • Official advisories

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

Exploitation likelihood is not on this record for AZL-113021. A missing EPSS score is not a low risk. Compare affecting package python-msgpack 1.2.3-1 with the linked advisory before you change production.

Which versions are affected?

Compare what you have installed with 0 → 1.2.3-1. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

No weakness class is stored. EPSS is not on this record yet. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Jun 22, 2026 · OpenSSF OSV / OSV Scanner

    Detected

    MessagePack for C# is a MessagePack serializer for C#. Prior to 2.5.301 and 3.1.7, when MessagePack-CSharp decompresses Lz4Block or Lz4BlockArray payloads, it reads declared uncompressed lengths from the wire and allocates output buffers based on those lengths before validating that the compressed data is valid or that the declared expansion is reasonable. A small payload can claim a very large un

  2. Nov 10, 2026 · OpenSSF OSV / OSV Scanner

    Fix available

    python-msgpack fixed in 1.2.3-1

  3. Nov 10, 2026 · OpenSSF OSV / OSV Scanner

    Updated

    MessagePack for C# is a MessagePack serializer for C#. Prior to 2.5.301 and 3.1.7, when MessagePack-CSharp decompresses Lz4Block or Lz4BlockArray payloads, it reads declared uncompressed lengths from the wire and allocates output buffers based on those lengths before validating that the compressed data is valid or that the declared expansion is reasonable. A small payload can claim a very large un

Sources

References

Freshness

Last verified in this catalog Nov 10, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • OpenSSF OSV / OSV ScannerNov 11, 2026