CVE-2023-51451 [Medium] | Security Vulnerability in Symbolicator

Symbolicator is a service used in Sentry. Starting in Symbolicator version 0.3.3 and prior to version 21.12.1, an attacker could make Symbolicator send GET HTTP requests to arbitrary URLs with internal IP addresses by using an invalid protocol. The responses of those requests could be exposed via Symbolicator's API. In affected Sentry instances, the data could be exposed through the Sentry API and user interface if the attacker has a registered account. The issue has been fixed in Symbolicator release 23.12.1, Sentry self-hosted release 23.12.1, and has already been mitigated on sentry.io on December 18, 2023. If updating is not possible, some other mitigations are available. One may disable JS processing by toggling the option `Allow JavaScript Source Fetching` in `Organization Settings > Security & Privacy` and/or disable all untrusted public repositories under `Project Settings > Debug Files`. Alternatively, if JavaScript and native symbolication are not required, disable Symbolicator completely in `config.yml`.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-06-15	0.28%	0.47%	+0.19%
2	2025-11-21	0.14%	0.28%	+0.15%
3	2025-11-18	—	0.14%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-06-15

0.28%

0.47%

+0.19%

2025-11-21

0.14%

0.28%

+0.15%

2025-11-18

—

0.14%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
4.3	3.1	MEDIUM	`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N` 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:L) A normal user session is enough; they don’t have to be admin. 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:L) Some sensitive info could get out, but not a total data dump. Integrity (I:N) Data isn’t meaningfully altered or forged. Availability (A:N) Service keeps running; no real outage angle.	2.8	1.4	[email protected]
4.3	3.1	MEDIUM	`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N` 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:L) A normal user session is enough; they don’t have to be admin. 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:L) Some sensitive info could get out, but not a total data dump. Integrity (I:N) Data isn’t meaningfully altered or forged. Availability (A:N) Service keeps running; no real outage angle.	2.8	1.4	[email protected]

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

4.3

3.1

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N 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:L): A normal user session is enough; they don’t have to be admin.
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:L): Some sensitive info could get out, but not a total data dump.
Integrity (I:N): Data isn’t meaningfully altered or forged.
Availability (A:N): Service keeps running; no real outage angle.

2.8

1.4

[email protected]

4.3

3.1

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N 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:L): A normal user session is enough; they don’t have to be admin.
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:L): Some sensitive info could get out, but not a total data dump.
Integrity (I:N): Data isn’t meaningfully altered or forged.
Availability (A:N): Service keeps running; no real outage angle.

2.8

1.4

[email protected]

Affected software / configurations for CVE-2023-51451

Vendor	Product	Version	Raw CPE
sentry	symbolicator	>= 0.3.3, < 23.12.1	cpe:2.3:a:sentry:symbolicator::::::::

References for CVE-2023-51451

URL	Tags
https://github.com/getsentry/self-hosted/releases/tag/23.12.1	Release Notes
https://github.com/getsentry/symbolicator/pull/1343	Patch
https://github.com/getsentry/symbolicator/releases/tag/23.12.1	Release Notes
https://github.com/getsentry/symbolicator/security/advisories/GHSA-ghg9-7m82-h96r	Mitigation Patch Vendor Advisory

URL

CVE-2023-51451 | SSRF in symbolicator via invalid protocol

Exploit prediction scoring system (EPSS) score for CVE-2023-51451

Common vulnerability scoring system (CVSS) metrics for CVE-2023-51451

Weakness enumeration for CVE-2023-51451

Affected software / configurations for CVE-2023-51451

References for CVE-2023-51451