CVE-2022-21688 [High] | Out-of-bounds Read in Onionshare

OnionShare is an open source tool that lets you securely and anonymously share files, host websites, and chat with friends using the Tor network. Affected versions of the desktop application were found to be vulnerable to denial of service via an undisclosed vulnerability in the QT image parsing. Roughly 20 bytes lead to 2GB memory consumption and this can be triggered multiple times. To be abused, this vulnerability requires rendering in the history tab, so some user interaction is required. An adversary with knowledge of the Onion service address in public mode or with authentication in private mode can perform a Denial of Service attack, which quickly results in out-of-memory for the server. This requires the desktop application with rendered history, therefore the impact is only elevated. This issue has been patched in version 2.5.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2025-11-21	0.29%	0.39%	+0.10%
2	2025-11-18	0.39%	0.29%	-0.10%
3	2025-09-11	—	0.39%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2025-11-21

0.29%

0.39%

+0.10%

2025-11-18

0.39%

0.29%

-0.10%

2025-09-11

—

0.39%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
7.5	3.1	HIGH	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H` Click to expand Attack vector (AV:N) Could be attacked over the internet or any normal routed network—not just someone sitting at the machine. Attack complexity (AC:L) Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup. Privileges required (PR:N) No account or special rights needed—anonymous or random user is enough. User interaction (UI:N) Nobody has to click “OK” or open a trap file; it can work without a victim helping. Scope (S:U) Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems. Confidentiality (C:N) Doesn’t really leak secrets in a meaningful way. Integrity (I:N) Data isn’t meaningfully altered or forged. Availability (A:H) Could take the service down hard or make it unusable for people who depend on it.	3.9	3.6	[email protected]
5.5	3.1	MEDIUM	`CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H` Click to expand Attack vector (AV:L) They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by. Attack complexity (AC:L) Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup. Privileges required (PR:N) No account or special rights needed—anonymous or random user is enough. User interaction (UI:R) A real person has to do something—click, install, enable—otherwise it doesn’t land. Scope (S:U) Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems. Confidentiality (C:N) Doesn’t really leak secrets in a meaningful way. Integrity (I:N) Data isn’t meaningfully altered or forged. Availability (A:H) Could take the service down hard or make it unusable for people who depend on it.	1.8	3.6	[email protected]
4.3	2.0	MEDIUM	`AV:N/AC:M/Au:N/C:N/I:N/A:P` Click to expand Access vector (AV:N) Can be exploited remotely over network reachability. Access complexity (AC:M) Exploitation needs some favorable conditions, but not exceptional ones. Authentication (AU:N) No authentication is required. Confidentiality impact (C:N) No confidentiality impact. Integrity impact (I:N) No integrity impact. Availability impact (A:P) Partial availability impact.	8.6	2.9	[email protected]

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

7.5

3.1

HIGH

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

Attack vector (AV:N): Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L): Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N): No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N): Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U): Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N): Doesn’t really leak secrets in a meaningful way.
Integrity (I:N): Data isn’t meaningfully altered or forged.
Availability (A:H): Could take the service down hard or make it unusable for people who depend on it.

3.9

3.6

[email protected]

5.5

3.1

MEDIUM

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

Attack vector (AV:L): They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L): Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N): No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R): A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U): Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N): Doesn’t really leak secrets in a meaningful way.
Integrity (I:N): Data isn’t meaningfully altered or forged.
Availability (A:H): Could take the service down hard or make it unusable for people who depend on it.

1.8

3.6

[email protected]

4.3

2.0

MEDIUM

AV:N/AC:M/Au:N/C:N/I:N/A:P Click to expand

Access vector (AV:N): Can be exploited remotely over network reachability.
Access complexity (AC:M): Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N): No authentication is required.
Confidentiality impact (C:N): No confidentiality impact.
Integrity impact (I:N): No integrity impact.
Availability impact (A:P): Partial availability impact.

8.6

2.9

[email protected]

OS Trackers for CVE-2022-21688

vendor	priority	summary	link
`ubuntu`	medium	CVE-2022-21688 medium priority: Ubuntu including 1 source packages (onionshare), 13 status rows across 13 suites (bionic, focal, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, trusty, upstream, xenial): ignored 6, not-affected 5, DNE 1, released 1.	https://ubuntu.com/security/CVE-2022-21688

Affected software / configurations for CVE-2022-21688

Vendor	Product	Version	Raw CPE
onionshare	onionshare	< 2.5	cpe:2.3:a:onionshare:onionshare::::::::

References for CVE-2022-21688

URL	Tags
https://github.com/onionshare/onionshare/releases/tag/v2.5	Release Notes Third Party Advisory
https://github.com/onionshare/onionshare/security/advisories/GHSA-x7wr-283h-5h2v	Third Party Advisory

URL

CVE-2022-21688 | Out-of-bounds Read in Onionshare

Exploit prediction scoring system (EPSS) score for CVE-2022-21688

Common vulnerability scoring system (CVSS) metrics for CVE-2022-21688

Weakness enumeration for CVE-2022-21688

GitHub Security Advisory for CVE-2022-21688

OS Trackers for CVE-2022-21688

Affected software / configurations for CVE-2022-21688

References for CVE-2022-21688