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CVE-2021-29510

Use of "infinity" as an input to datetime and date fields causes infinite loop in pydantic

3.3 LowFix available

Pydantic is a data validation and settings management using Python type hinting. In affected versions passing either 'infinity', 'inf' or float('inf') (or their negatives) to datetime or date fields causes validation to run forever with 100% CPU usage (on one CPU). Pydantic has been patched with fixes available in the following versions: v1.8.2, v1.7.4, v1.6.2. All these versions are available on pypi(https://pypi.org/project/pydantic/#history), and will be available on conda-forge(https://anaconda.org/conda-forge/pydantic) soon. See the changelog(https://pydantic-docs.helpmanual.io/) for details. If you absolutely can't upgrade, you can work around this risk using a validator(https://pydantic-docs.helpmanual.io/usage/validators/) to catch these values. This is not an ideal solution (in particular you'll need a slightly different function for datetimes), instead of a hack like this you should upgrade pydantic. If you are not using v1.8.x, v1.7.x or v1.6.x and are unable to upgrade to a fixed version of pydantic, please create an issue at https://github.com/samuelcolvin/pydantic/issues requesting a back-port, and we will endeavour to release a patch for earlier versions of pydantic.

Attack profile

How easy it is to exploit

Attack vector
Local
Complexity
Low
Privileges needed
None
User interaction
Required

What an attacker can affect

Confidentiality
None
Integrity
None
Availability
Low

Exploit likelihood

0.97%Up 0.4 points since May 14, 2021
90%50%10%1%

What each source reports

CVE List Score used 3.3

Use of "infinity" as an input to datetime and date fields causes infinite loop in pydantic

Pydantic is a data validation and settings management using Python type hinting. In affected versions passing either 'infinity', 'inf' or float('inf') (or their negatives) to datetime or date fields causes validation to run forever with 100% CPU usage (on one CPU). Pydantic has been patched with fixes available in the following versions: v1.8.2, v1.7.4, v1.6.2. All these versions are available on pypi(https://pypi.org/project/pydantic/#history), and will be available on conda-forge(https://anaconda.org/conda-forge/pydantic) soon. See the changelog(https://pydantic-docs.helpmanual.io/) for details. If you absolutely can't upgrade, you can work around this risk using a validator(https://pydantic-docs.helpmanual.io/usage/validators/) to catch these values. This is not an ideal solution (in particular you'll need a slightly different function for datetimes), instead of a hack like this you should upgrade pydantic. If you are not using v1.8.x, v1.7.x or v1.6.x and are unable to upgrade to a fixed version of pydantic, please create an issue at https://github.com/samuelcolvin/pydantic/issues requesting a back-port, and we will endeavour to release a patch for earlier versions of pydantic.

Record
CVE-2021-29510
CVSS 3.1
3.3 LowCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L
Weakness
CWE-835
Updated
2026-11-02
EUVDEUVD-2021-0206 3.3

Pydantic is a data validation and settings management using Python type hinting. In affected versions passing either 'infinity', 'inf' or float('inf') (or their negatives) to datetime or date fields causes validation to run forever with 100% CPU usage (on one CPU). Pydantic has been patched with fixes available in the following versions: v1.8.2, v1.7.4, v1.6.2. All these versions are available on pypi(https://pypi.org/project/pydantic/#history), and will be available on conda-forge(https://anaconda.org/conda-forge/pydantic) soon. See the changelog(https://pydantic-docs.helpmanual.io/) for details. If you absolutely can't upgrade, you can work around this risk using a validator(https://pydantic-docs.helpmanual.io/usage/validators/) to catch these values. This is not an ideal solution (in particular you'll need a slightly different function for datetimes), instead of a hack like this you should upgrade pydantic. If you are not using v1.8.x, v1.7.x or v1.6.x and are unable to upgrade to a fixed version of pydantic, please create an issue at https://github.com/samuelcolvin/pydantic/issues requesting a back-port, and we will endeavour to release a patch for earlier versions of pydantic.

Record
EUVD-2021-0206
CVSS 3.1
3.3 LowCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L
Updated
2026-11-03
GitHub AdvisoriesGHSA-5jqp-qgf6-3pvh 5.3

Use of "infinity" as an input to datetime and date fields causes infinite loop in pydantic

Impact

Passing either 'infinity', 'inf' or float('inf') (or their negatives) to datetime or date fields causes validation to run forever with 100% CPU usage (on one CPU). Patches

Pydantic is be patched with fixes available in the following versions:

v1.8.2
v1.7.4
v1.6.2

All these versions are available on pypi, and will be available on conda-forge soon.

See the changelog for details. Workarounds

If you absolutely can't upgrade, you can work around this risk using a validator to catch these values, brief demo:

from datetime import date from pydantic import BaseModel, validator

class DemoModel(BaseModel): date_of_birth: date

@validator('date_of_birth', pre=True)
def skip_infinite_values(cls, v):
    try:
        seconds = float(v)
    except (ValueError, TypeError):
        return v
    else:
        if seconds == float('inf'):
            return date.max
        elif seconds == float('-inf'):
            return date.min
        else:
            return seconds

Note: this is not an ideal solution (in particular you'll need a slightly different function for datetimes), instead of a hack like this you should upgrade pydantic.

If you are not using v1.8.x, v1.7.x or v1.6.x and are unable to upgrade to a fixed version of pydantic, please create an issue requesting a back-port, and we will endeavour to release a patch for earlier versions of pydantic. References

This was fixed in commit 7e83fdd.

Record
GHSA-5jqp-qgf6-3pvh
CVSS 4.0
5.3 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
CVSS 3.1
3.3 LowCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L
Weakness
CWE-835
Updated
2026-11-02
NVD 3.3

Pydantic is a data validation and settings management using Python type hinting. In affected versions passing either 'infinity', 'inf' or float('inf') (or their negatives) to datetime or date fields causes validation to run forever with 100% CPU usage (on one CPU). Pydantic has been patched with fixes available in the following versions: v1.8.2, v1.7.4, v1.6.2. All these versions are available on pypi(https://pypi.org/project/pydantic/#history), and will be available on conda-forge(https://anaconda.org/conda-forge/pydantic) soon. See the changelog(https://pydantic-docs.helpmanual.io/) for details. If you absolutely can't upgrade, you can work around this risk using a validator(https://pydantic-docs.helpmanual.io/usage/validators/) to catch these values. This is not an ideal solution (in particular you'll need a slightly different function for datetimes), instead of a hack like this you should upgrade pydantic. If you are not using v1.8.x, v1.7.x or v1.6.x and are unable to upgrade to a fixed version of pydantic, please create an issue at https://github.com/samuelcolvin/pydantic/issues requesting a back-port, and we will endeavour to release a patch for earlier versions of pydantic.

Record
CVE-2021-29510
CVSS 3.1
3.3 LowCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS 2.0
5.0 MediumAV:N/AC:L/Au:N/C:N/I:N/A:P
Weakness
CWE-835
Updated
2026-11-02
OSV 7.5

Pydantic is a data validation and settings management using Python type hinting. In affected versions passing either 'infinity', 'inf' or float('inf') (or their negatives) to datetime or date fields causes validation to run forever with 100% CPU usage (on one CPU). Pydantic has been patched with fixes available in the following versions: v1.8.2, v1.7.4, v1.6.2. All these versions are available on pypi(https://pypi.org/project/pydantic/#history), and will be available on conda-forge(https://anaconda.org/conda-forge/pydantic) soon. See the changelog(https://pydantic-docs.helpmanual.io/) for details. If you absolutely can't upgrade, you can work around this risk using a validator(https://pydantic-docs.helpmanual.io/usage/validators/) to catch these values. This is not an ideal solution (in particular you'll need a slightly different function for datetimes), instead of a hack like this you should upgrade pydantic. If you are not using v1.8.x, v1.7.x or v1.6.x and are unable to upgrade to a fixed version of pydantic, please create an issue at https://github.com/samuelcolvin/pydantic/issues requesting a back-port, and we will endeavour to release a patch for earlier versions of pydantic.

Record
CVE-2021-29510
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-02
OSVDEBIAN-CVE-2021-29510 7.5

Pydantic is a data validation and settings management using Python type hinting. In affected versions passing either 'infinity', 'inf' or float('inf') (or their negatives) to datetime or date fields causes validation to run forever with 100% CPU usage (on one CPU). Pydantic has been patched with fixes available in the following versions: v1.8.2, v1.7.4, v1.6.2. All these versions are available on pypi(https://pypi.org/project/pydantic/#history), and will be available on conda-forge(https://anaconda.org/conda-forge/pydantic) soon. See the changelog(https://pydantic-docs.helpmanual.io/) for details. If you absolutely can't upgrade, you can work around this risk using a validator(https://pydantic-docs.helpmanual.io/usage/validators/) to catch these values. This is not an ideal solution (in particular you'll need a slightly different function for datetimes), instead of a hack like this you should upgrade pydantic. If you are not using v1.8.x, v1.7.x or v1.6.x and are unable to upgrade to a fixed version of pydantic, please create an issue at https://github.com/samuelcolvin/pydantic/issues requesting a back-port, and we will endeavour to release a patch for earlier versions of pydantic.

Record
DEBIAN-CVE-2021-29510
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-02
Show 7 moreShow less
OSVGHSA-5jqp-qgf6-3pvh 5.3

Use of "infinity" as an input to datetime and date fields causes infinite loop in pydantic

Impact

Passing either 'infinity', 'inf' or float('inf') (or their negatives) to datetime or date fields causes validation to run forever with 100% CPU usage (on one CPU). Patches

Pydantic is be patched with fixes available in the following versions:

v1.8.2
v1.7.4
v1.6.2

All these versions are available on pypi, and will be available on conda-forge soon.

See the changelog for details. Workarounds

If you absolutely can't upgrade, you can work around this risk using a validator to catch these values, brief demo:

from datetime import date from pydantic import BaseModel, validator

class DemoModel(BaseModel): date_of_birth: date

@validator('date_of_birth', pre=True)
def skip_infinite_values(cls, v):
    try:
        seconds = float(v)
    except (ValueError, TypeError):
        return v
    else:
        if seconds == float('inf'):
            return date.max
        elif seconds == float('-inf'):
            return date.min
        else:
            return seconds

Note: this is not an ideal solution (in particular you'll need a slightly different function for datetimes), instead of a hack like this you should upgrade pydantic.

If you are not using v1.8.x, v1.7.x or v1.6.x and are unable to upgrade to a fixed version of pydantic, please create an issue requesting a back-port, and we will endeavour to release a patch for earlier versions of pydantic. References

This was fixed in commit 7e83fdd.

Record
GHSA-5jqp-qgf6-3pvh
CVSS 4.0
5.3 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
CVSS 3.1
3.3 LowCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L
Weakness
CWE-835
Updated
2026-11-02
OSVUBUNTU-CVE-2021-29510 3.3

Pydantic is a data validation and settings management using Python type hinting. In affected versions passing either 'infinity', 'inf' or float('inf') (or their negatives) to datetime or date fields causes validation to run forever with 100% CPU usage (on one CPU). Pydantic has been patched with fixes available in the following versions: v1.8.2, v1.7.4, v1.6.2. All these versions are available on pypi(https://pypi.org/project/pydantic/#history), and will be available on conda-forge(https://anaconda.org/conda-forge/pydantic) soon. See the changelog(https://pydantic-docs.helpmanual.io/) for details. If you absolutely can't upgrade, you can work around this risk using a validator(https://pydantic-docs.helpmanual.io/usage/validators/) to catch these values. This is not an ideal solution (in particular you'll need a slightly different function for datetimes), instead of a hack like this you should upgrade pydantic. If you are not using v1.8.x, v1.7.x or v1.6.x and are unable to upgrade to a fixed version of pydantic, please create an issue at https://github.com/samuelcolvin/pydantic/issues requesting a back-port, and we will endeavour to release a patch for earlier versions of pydantic.

Record
UBUNTU-CVE-2021-29510
CVSS 3.1
3.3 LowCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-02
OSVopenSUSE-SU-2024:11254-1 No score

python36-pydantic-1.8.2-1.2 on GA media

These are all security issues fixed in the python36-pydantic-1.8.2-1.2 package on the GA media of openSUSE Tumbleweed.

Record
openSUSE-SU-2024:11254-1
Updated
2026-11-02
OSVopenSUSE-SU-2024:13869-1 No score

python310-pydantic-2.6.4-2.1 on GA media

These are all security issues fixed in the python310-pydantic-2.6.4-2.1 package on the GA media of openSUSE Tumbleweed.

Record
openSUSE-SU-2024:13869-1
Updated
2026-11-02
OSVopenSUSE-SU-2026:11424-1 No score

python313-pydantic-2.13.4-2.1 on GA media

These are all security issues fixed in the python313-pydantic-2.13.4-2.1 package on the GA media of openSUSE Tumbleweed.

Record
openSUSE-SU-2026:11424-1
Updated
2026-11-02
OSVPYSEC-2021-47 No score

Pydantic is a data validation and settings management using Python type hinting. In affected versions passing either 'infinity', 'inf' or float('inf') (or their negatives) to datetime or date fields causes validation to run forever with 100% CPU usage (on one CPU). Pydantic has been patched with fixes available in the following versions: v1.8.2, v1.7.4, v1.6.2. All these versions are available on pypi(https://pypi.org/project/pydantic/#history), and will be available on conda-forge(https://anaconda.org/conda-forge/pydantic) soon. See the changelog(https://pydantic-docs.helpmanual.io/) for details. If you absolutely can't upgrade, you can work around this risk using a validator(https://pydantic-docs.helpmanual.io/usage/validators/) to catch these values. This is not an ideal solution (in particular you'll need a slightly different function for datetimes), instead of a hack like this you should upgrade pydantic. If you are not using v1.8.x, v1.7.x or v1.6.x and are unable to upgrade to a fixed version of pydantic, please create an issue at https://github.com/samuelcolvin/pydantic/issues requesting a back-port, and we will endeavour to release a patch for earlier versions of pydantic.

Record
PYSEC-2021-47
Updated
2026-11-02
OSVUSN-6553-1 No score

pydantic vulnerability

Nina Jensen discovered that Pydantic incorrectly handled user input in the date and datetime fields. An attacker could possibly use this issue to cause a denial of service via application crash. (CVE-2021-29510)

Record
USN-6553-1
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
pydantic
PyPI
before 1.6.2
1.6.2
pydantic
PyPI
1.8 up to 1.8.2
1.8.2
pydantic
PyPI
1.7 up to 1.7.4
1.7.4
pydantic
Debian:12
before 1.7.4-1
1.7.4-1
pydantic
Debian:13
before 1.7.4-1
1.7.4-1
pydantic
Debian:14
before 1.7.4-1
1.7.4-1
pydantic
PyPI
before 1.6.2, plus listed versions
0.0.10.0.20.0.30.0.40.0.5
Show 45 moreShow less
0.0.60.0.70.0.80.10.100.110.11.10.11.20.120.12.10.130.13.10.140.150.160.16.10.170.180.18.10.18.20.190.20.2.10.200.20.10.20a10.210.220.230.240.250.260.270.27a10.280.290.30.300.30.10.310.31.10.320.32.10.32.20.4
1.6.2
pydantic
PyPI
1.8 up to 1.8.2, plus listed versions
1.8.1
1.8.2
pydantic
PyPI
1.7 up to 1.7.4, plus listed versions
1.7.11.7.21.7.3
1.7.4
pydantic
PyPI
before 1.6.2, 1.7 up to 1.7.4, 1.8 up to 1.8.2, plus listed versions
0.0.10.0.20.0.30.0.40.0.5
Show 45 moreShow less
0.0.60.0.70.0.80.10.100.110.11.10.11.20.120.12.10.130.13.10.140.150.160.16.10.170.180.18.10.18.20.190.20.2.10.200.20.10.20a10.210.220.230.240.250.260.270.27a10.280.290.30.300.30.10.310.31.10.320.32.10.32.20.4
1.6.21.7.41.8.2
pydantic
Ubuntu:Pro:20.04:LTS
before 1.2-1ubuntu0.1~esm1, plus listed versions
0.30.1-11.2-1
1.2-1ubuntu0.1~esm1
python-pydantic
openSUSE:Tumbleweed
From an advisory covering 2 CVEs
before 2.13.4-2.1
2.13.4-2.1

History

History
RecordedChangedSources
affected, facts
aliasesEUVD
first indexedCVE List, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2021-29510 is a low vulnerability (CVSS 3.3) in Pydantic, published May 13, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.97%, the 62nd percentile. Fixed in pydantic 1.6.2.

References

Show 15 moreShow less
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Left out here: 123 versions. The JSON record has them.

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