VulnerabilityPublished 27 Dec 2024Updated 3 Nov 2025

CVE-2024-56520: tecnick tcpdf

Affects tecnick tcpdfSource CVE Database V5

Not known to be exploited · CVSS 7.3 High · fixed in 2.6.4 : patch tecnick tcpdf soon.

Data as of 26 Oct 2026, 10:12 UTC

CVSS 3.1 base score

7.3High

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.5% chance of exploitation in 30 days – higher than 46% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 2.6.4, 6.8.0

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: Low
Integrity: Low
Availability: Low

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the impacted component.
Integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact on the impacted component.
Availability: Low: Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the impacted component are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 27 Dec 2024
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade tecnickcom/tc-lib-pdf-font to 2.6.4; tecnickcom/TCPDF to 6.8.0.

Affected software

Product	Affected	Fixed in
GitHubtecnickcom/tc-lib-pdf-font`pkg:github/tecnickcom/tc-lib-pdf-font`Other threats	Affected <2.6.4	Fixed in 2.6.4
GitHubtecnickcom/TCPDF`pkg:github/tecnickcom/TCPDF`Other threats	Affected <6.8.0	Fixed in 6.8.0

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

European organizations should immediately assess their use of TCPDF and tc-lib-pdf-font components, identifying any instances of versions prior to TCPDF 6.8.0 and tc-lib-pdf-font 2.6.4. The primary mitigation is to upgrade these libraries to the fixed versions or later. Where upgrading is not immediately feasible, organizations should implement strict input validation and sanitization on PDF font data, restrict PDF generation to trusted sources, and monitor PDF processing logs for anomalies. Employing web application firewalls (WAFs) with rules targeting malformed PDF payloads may provide temporary protection. Security teams should also review document handling workflows to detect suspicious activity and ensure that PDF generation services run with least privilege. Regular vulnerability scanning and patch management processes should be reinforced to prevent exploitation. Finally, organizations should stay informed about any emerging exploit reports related to this vulnerability to adjust defenses accordingly.

Description

An issue was discovered in tc-lib-pdf-font before 2.6.4, as used in TCPDF before 6.8.0 and other products. Fonts are mishandled, e.g., FontBBox for Type 1 and TrueType fonts is misparsed.

Impact

For European organizations, the vulnerability poses risks across multiple sectors that rely on PDF generation and processing, including government agencies, financial institutions, healthcare providers, and software vendors. Exploitation could lead to unauthorized disclosure of sensitive information embedded in PDFs, manipulation of official documents, or disruption of services dependent on PDF workflows. Given the remote and unauthenticated nature of the exploit, attackers could leverage this vulnerability to compromise web applications or backend systems that generate or handle PDFs, potentially leading to broader network infiltration or data breaches. The impact is heightened in environments where PDF documents are used for critical communications, contracts, or regulatory compliance. Additionally, denial of service conditions could disrupt business operations or public services. The lack of known exploits currently provides a window for proactive defense, but the high CVSS score indicates a strong likelihood of future exploit development.

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 3 Nov 2025, 20:04 UTC

Technical details

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