CVE-2021-45958

mediumpriority · track · 23EPSS 0.017 · 77 %ileEUUS

grimoire priorityP3 · Track

Exploitable?

—

no known exploitation

Likely / severe?

1.67% (77th) EPSS

CVSS 4.3 · medium

Is it mine?

8 products

Check your exposure

Who says so?

4 sources

cnnvd · enisa_euvd · osv · nvd

EPSS · scored 2026-10-27

UltraJSON (aka ujson) through 5.1.0 has a stack-based buffer overflow in Buffer_AppendIndentUnchecked (called from encode). Exploitation can, for example, use a large amount of indentation.

cvss

Technical severity, 0–10. One row per scoring source.

5.5

010

base score 0–10 · higher = more severe · hover a vector to decode

v2.04.3mediumAV:N/AC:M/Au:N/C:N/I:N/A:Pprimary · NVD / NIST USexploitability 8.6 · impact 2.9

v3.15.5mediumCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:Hprimary · NVD / NIST USexploitability 1.8 · impact 3.6

v3.15.5mediumCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:Hsecondary · OSV

v3.15.1mediumCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H/E:Usecondary · CVSS-BT (t0sche)

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-787USprimaryCWE-787US

affected products (8)

Products and version ranges known to be affected.

n/a n/a≤ n/aenisa_euvdEU
debian debian linux= 9.0nvdUScpe:2.3:o:debian:debian_linux:*:*:*:*:*:*:*:*
fedoraproject fedora= 35nvdUScpe:2.3:o:fedoraproject:fedora:*:*:*:*:*:*:*:*
fedoraproject fedora= 36nvdUScpe:2.3:o:fedoraproject:fedora:*:*:*:*:*:*:*:*
fedoraproject fedora= 37nvdUScpe:2.3:o:fedoraproject:fedora:*:*:*:*:*:*:*:*
ultrajson project ultrajson< 5.2.0nvdUScpe:2.3:a:ultrajson_project:ultrajson:*:*:*:*:*:*:*:*
PyPI ujson1.34 → 5.2.0osvUSpkg:pypi/ujson
PyPI ujson4.0.2 → 5.1.0osvUSpkg:pypi/ujson

advisories (2)

Vendor and ecosystem advisories describing this.

GHSA-fh56-85cw-5pq6UltraJSON vulnerable to Out-of-bounds Write2022-01-21ghsa · osvUS
UltraJSON (aka ujson) 1.34 through 5.1.0 has a stack-based buffer overflow in Buffer_AppendIndentUnchecked (called from encode).
PYSEC-2022-252022-01-01vendor · osvUS
UltraJSON (aka ujson) through 5.1.0 has a stack-based buffer overflow in Buffer_AppendIndentUnchecked (called from encode). Exploitation can, for example, use a large amount of indentation.

also known as (6)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd osv nvd NVD CVE.org MITRE

published 2022-01-01modified 2026-06-17

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+16132 more

references (35)

External citations — patches, advisories, analysis.

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