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CVE-2021-27836

23
FAUCET Score

CVE-2021-27836 is a denial-of-service vulnerability in libxls 1.6.2, specifically within the xls_getWorkSheet function in xls.c, affecting products like Fedora and libxls_project. An unauthenticated attacker can trigger this by tricking a user into opening a specially crafted XLS file, leading to a high impact on availability. While rated Medium severity (CVSS 6.5), there is no evidence of active exploitation, public exploit code, or significant community discussion surrounding this vulnerability.

Impacted Technologies

VendorProductVersion(s)CPE
1.6.2CPE matchmatch criteria
cpe:2.3:a:libxls_project:libxls:1.6.2:-:*:*:*:*:*:*
33CPE matchmatch criteria
cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*
34CPE matchmatch criteria
cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*
35CPE matchmatch criteria
cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

6.5MEDIUM

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

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
Exploitability Score
2.8
Impact Score
3.6
CvssVersion
3.1

Exploit Intelligence

EPSS Score
1.12%
Probability of exploitation in next 30 days
EPSS Percentile
62.8%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0112 is in the 75th percentile among its peer group of 26,234 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.0 Mastodon, and 0.1 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (1)

github_advisorypatch availablevia nvd_reference
View patch

References

github.com / libxls/libxls/issues/94
PatchThird Party Advisory
lists.fedoraproject.org / archives/list/package-announce%40lists.fedoraproject.org/message/5D7XXCVFYRRMI4ENXYSD3MZEBS6SMI7E
lists.fedoraproject.org / archives/list/package-announce%40lists.fedoraproject.org/message/SFOE4Z6T46LA47VXWUVET4ELXRZQ3BWB
lists.fedoraproject.org / archives/list/package-announce%40lists.fedoraproject.org/message/Y6XOTFEOCHYKZAFCB6H3KNIIFJ3UFV7V