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Vulnerabilities

Vulnerability · HSEC-2026-0007

Denial of Service and Memory Exhaustion in aeson

Published May 22, 2026 · catalog updated Sep 16, 2026 · Denial of Service and

Open the advisory

Exploitation likelihood is not on this record for HSEC-2026-0007. A missing EPSS score is not a low risk. Compare Denial of Service and 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 (Denial of Service and).
  • 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
Hackage aeson · Hackage text-iso8601

# Denial of Service and Memory Exhaustion in aeson A Denial of Service (DoS) and memory exhaustion vulnerability was identified in the package. The vulnerability allows an attacker to exhaust server memory and crash the host process by supplying maliciously crafted JSON payloads. The vulnerability exists in 's function (located in ). The exponent bounds check only rejects large positive exponents ( ) but fails to reject arbitrarily large negative exponents. When an attacker sends a JSON number with a massive negative exponent (e.g., ), the value bypasses the check and flows into , which computes . For such a large negative exponent, produces a GMP Integer with approximately 1 billion decimal digits, causing immediate and severe memory exhaustion. Affected instances: * (including , , , etc.) * * ## Resolution The issue was resolved by introducing proper bounds checks: - now applies an absolute bounds check to both positive and negative exponents ( ). The fix first shipped in , and have been backported to the previous release series as . Users are strongly advised to update to the patched versions: * or later ## Acknowledgements The vulnerabilities were reported Nathan Walsh, and patched by Li-yao Xia.

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.

  • Hackage aeson0.12.0.0 → 2.2.5.1
  • Hackage text-iso86010.1 → 0.1.1.2

How to fix HSEC-2026-0007

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 HSEC-2026-0007. A missing EPSS score is not a low risk. Compare Denial of Service and with the linked advisory before you change production.

Which versions are affected?

Compare what you have installed with 0.12.0.0 → 2.2.5.1, 0.1 → 0.1.1.2. 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.

Timeline

Detection, updates, and resolution for this record.

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

    Detected

    # Denial of Service and Memory Exhaustion in aeson A Denial of Service (DoS) and memory exhaustion vulnerability was identified in the package. The vulnerability allows an attacker to exhaust server memory and crash the host process by supplying maliciously crafted JSON payloads. The vulnerability exists in 's function (located in ). The exponent bounds check only rejects large positive exponents

  2. Sep 16, 2026 · OpenSSF OSV / OSV Scanner

    Fix available

    aeson fixed in 2.2.5.1; text-iso8601 fixed in 0.1.1.2

  3. Sep 16, 2026 · OpenSSF OSV / OSV Scanner

    Fix available

    aeson fixed in 2.2.5.1

  4. Sep 16, 2026 · OpenSSF OSV / OSV Scanner

    Fix available

    text-iso8601 fixed in 0.1.1.2

  5. Sep 16, 2026 · OpenSSF OSV / OSV Scanner

    Updated

    # Denial of Service and Memory Exhaustion in aeson A Denial of Service (DoS) and memory exhaustion vulnerability was identified in the package. The vulnerability allows an attacker to exhaust server memory and crash the host process by supplying maliciously crafted JSON payloads. The vulnerability exists in 's function (located in ). The exponent bounds check only rejects large positive exponents

Sources

References

Freshness

Last verified in this catalog Sep 16, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.