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CVE-2021-21707

MEDIUMCVSS 5.3/10EPSS 25.95%

Last modified

CVE-2021-21707 is a medium-severity vulnerability rated 5.3/10 on the CVSS scale. In PHP versions 7.3.x below 7.3.33, 7.4.x below 7.4.26 and 8.0.x below 8.0.13, certain XML parsing functions, like simplexml_load_file(), URL-decode the filename passed to them. If that filename contains URL-encoded NUL character, this may cause the function to interpret this as the end of the filename, thus interpreting the filename differently from what the user intended, which may lead it to reading a different file than intended.. EPSS estimates a 25.95% chance of exploitation in the next 30 days.

Description

In PHP versions 7.3.x below 7.3.33, 7.4.x below 7.4.26 and 8.0.x below 8.0.13, certain XML parsing functions, like simplexml_load_file(), URL-decode the filename passed to them. If that filename contains URL-encoded NUL character, this may cause the function to interpret this as the end of the filename, thus interpreting the filename differently from what the user intended, which may lead it to reading a different file than intended.

Metrics

CVSS 3.1
5.3/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

EPSS Probability
25.95%

97.7th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
PhpPhp>= 7.3.0, < 7.3.33
PhpPhp>= 7.4.0, < 7.4.26
PhpPhp>= 8.0.0, < 8.0.13
NetappClustered Data OntapAll versions
DebianDebian Linux10.0
DebianDebian Linux11.0
TenableTenable.Sc< 5.21.0

References

Timeline

Published
Last Modified
Status
Modified

Frequently Asked Questions

What is CVE-2021-21707?
In PHP versions 7.3.x below 7.3.33, 7.4.x below 7.4.26 and 8.0.x below 8.0.13, certain XML parsing functions, like simplexml_load_file(), URL-decode the filename passed to them. If that filename contains URL-encoded NUL character, this may cause the function to interpret this as the end of the filename, thus interpreting the filename differently from what the user intended, which may lead it to reading a different file than intended.
How severe is CVE-2021-21707?
CVE-2021-21707 has a CVSS score of 5.3/10 (MEDIUM severity). The EPSS model estimates a 25.95% probability of exploitation in the next 30 days.
How do I fix CVE-2021-21707?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-21707?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST