# RHSA-2021:3755: firefox security update

RHSA-2021:3755, released October 11, 2021, fixes 6 CVEs in firefox (version 0:91.2.0-4.el8_4). None of them is reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/fix/linux/rhsa-2021-3755
- Platform: Linux
- Released: Oct 11, 2021
- Priority: High (Closes CVE-2021-32810, high severity)
- CVEs: 6, exploited: 0, on CISA KEV: 0
- Vendor advisory: https://access.redhat.com/errata/RHSA-2021:3755

## Applies to

| Product | Release | Fixed in |
|---|---|---|
| [firefox](https://patchblox.com/security/data/product/linux/firefox.md) | RHEL 8 | 0:91.2.0-4.el8_4 |

## CVEs this fix closes

| CVE | Priority | Title | CVSS | EPSS | Exploitation |
|---|---|---|---:|---:|---|
| [CVE-2021-32810](https://patchblox.com/security/data/cve/CVE-2021-32810.md) | High | firefox: crossbeam-deque is a package of work-stealing deques for building taskschedulers when programming in Rust | 9.8 | 0.0191 |  |
| [CVE-2021-38496](https://patchblox.com/security/data/cve/CVE-2021-38496.md) | High | Mozilla Firefox ESR and 3 others: During operations on MessageTasks, a task may have been removed while it was still scheduled, resulting… | 8.8 | 0.0166 |  |
| [CVE-2021-38498](https://patchblox.com/security/data/cve/CVE-2021-38498.md) | High | Mozilla Firefox ESR and 3 others: During process shutdown, a document could have caused a use-after-free of a languages service object,… | 7.5 | 0.0147 |  |
| [CVE-2021-38500](https://patchblox.com/security/data/cve/CVE-2021-38500.md) | High | Mozilla Firefox ESR and 3 others: Mozilla developers reported memory safety bugs present in Firefox 92 and Firefox ESR 91.1. | 8.8 | 0.0127 |  |
| [CVE-2021-38501](https://patchblox.com/security/data/cve/CVE-2021-38501.md) | High | Mozilla Firefox ESR and 3 others: Mozilla developers reported memory safety bugs present in Firefox 92 and Firefox ESR 91.1. | 8.8 | 0.0105 |  |
| [CVE-2021-38497](https://patchblox.com/security/data/cve/CVE-2021-38497.md) | Routine | Mozilla Firefox ESR and 3 others: Through use of reportValidity() and window.open(), a plain-text validation message could have been overlaid… | 6.5 | 0.0059 |  |

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Data as of 2026-11-07T12:40:37Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo